CalcGallery

Free calculators for money, math, school and home projects

Work out a loan payment, a percentage, a paycheck, a grade or how much concrete a slab needs. Every calculator shows the formula it used and the assumptions behind it.

Most used

Finance

Loans, mortgages, debt payoff, interest and savings.

Retirement and investing

Retirement savings, IRAs, pensions, withdrawal rates, present and future value, annuities and investment returns, on the assumptions you enter.

Retirement planning

Retirement savings, 401(k) matches, Roth and traditional IRAs, pensions, FIRE numbers and withdrawal rates, on your own assumptions.

  • Tax-Adjusted Asset Allocation Calculator

    Your stock and bond split with pre-tax balances reduced by the tax you expect to pay on withdrawal, beside the split your statements show. One way to view an allocation.

  • Retirement Savings Calculator

    What your savings and monthly contributions could grow to by retirement, in future money and in today’s, on the return and inflation you choose.

  • 401(k) Calculator

    Your 401(k) at retirement with your employer’s match modelled tier by tier, and how much match you leave unclaimed by contributing less than it covers.

  • Roth IRA Calculator

    A Roth IRA against a traditional IRA on the same out-of-pocket cost, after tax, and the retirement tax rate at which the two come out equal.

  • Traditional IRA Calculator

    The tax a traditional IRA contribution saves this year, what the account grows to and leaves after tax, and what deferral is worth against a taxable account.

  • Pension Calculator

    A defined-benefit pension from salary, accrual rate and years of service, adjusted for retiring early or late, and the lump sum it is worth today.

  • FIRE Number Calculator

    The savings needed to live off your investments at the withdrawal rate you choose, how many years it takes at your savings rate, and your coast number.

  • Safe Withdrawal Rate Calculator

    How much a portfolio can pay out each year in today’s money for as long as you need it, and how long a withdrawal you choose would last.

  • EPF Calculator

    What your Employees’ Provident Fund grows to by retirement from your basic pay, with the employer’s split between EPF and the pension scheme and the ₹25,000 ceiling.

  • Gratuity Calculator

    Gratuity under the Code on Social Security from your last drawn wages and years of service, with the six-month rounding rule and the tax-free limit.

  • Salary Sacrifice Pension Calculator

    What paying into your pension by salary sacrifice really costs your take-home pay in 2026/27, after the income tax and National Insurance it saves.

  • Social Security Claiming Age Calculator

    See how your monthly Social Security retirement benefit changes if you claim at any age from 62 to 70, and when waiting pays off.

  • RMD Calculator

    Work out the required minimum distribution from an IRA or 401(k) for any year, using the IRS Uniform Lifetime Table and the SECURE 2.0 starting ages.

  • IRMAA Calculator 2026

    Find your 2026 Medicare Part B premium and Part D surcharge (IRMAA) from your 2024 income, for single, joint and separate filers.

  • HSA Contribution Calculator 2026

    How much you can put in a health savings account in 2026, after employer contributions, and the tax it saves, for self-only or family coverage.

  • RRSP Tax Refund Calculator 2026

    The tax refund an RRSP contribution gives you for 2026 in your province, worked out by running your whole tax bill with and without it.

  • TFSA Contribution Room Calculator 2026

    Your Tax-Free Savings Account contribution room for 2026 from your age, the year you became resident, what you have put in and what you have taken out.

  • OAS Clawback Calculator

    How much Old Age Security you repay through the recovery tax when your net income is above the threshold, and how much you keep.

  • CPP Start Age Calculator

    How your Canada Pension Plan retirement pension changes if you start it at any age from 60 to 70, and when waiting pays off.

  • Super Guarantee Calculator 2026–27

    The 12% superannuation guarantee your employer must pay on your earnings in 2026–27, up to the maximum contribution base.

  • Salary Sacrifice Super Calculator 2026–27

    What salary sacrificing into super costs your take-home pay in 2026–27, how much more reaches your super, and the net gain after contributions tax.

  • NPS Calculator

    What your National Pension System account could grow to by 60, the lump sum you can take under the 2025 exit rules, and the pension from the rest.

Time value of money

Future and present value, annuities, annuity payouts, CDs and the rule of 72, at every compounding frequency.

  • Future Value Calculator

    What a present amount and regular payments grow to at any compounding frequency, from annual to continuous, with the effective annual rate.

  • Present Value Calculator

    What a future sum, a series of payments or a perpetuity is worth today at the discount rate you choose, with the discount factor.

  • Annuity Calculator

    An annuity in two phases: what a starting amount and regular contributions grow to, then the level payment that value pays out over a fixed term.

  • Annuity Payout Calculator

    The level income a lump sum pays over the years you choose, the interest-only income that never touches it, and how long a payment you pick would last.

  • CD Calculator

    What a certificate of deposit is worth at maturity from a quoted APY or a nominal rate, the APY a nominal rate gives, the early withdrawal penalty and a ladder.

  • Rule of 72 Calculator

    How long money takes to double, triple or quadruple by the rule of 72 and exactly, with the error between them, and the rate needed for a given time.

  • Inflation Calculator

    What an amount will cost, or be worth in today’s money, after years of inflation at a yearly rate you choose. Not based on CPI history.

  • APY Calculator

    Convert a nominal interest rate to its annual percentage yield and back at any compounding, or find the APY of an account from the interest it paid.

  • TVM Calculator

    Solve any one of the five time value of money keys, N, I/Y, PV, PMT or FV, the way a financial calculator does.

Investment returns

CAGR, stock profit after costs and tax, dividend yield, dividend reinvestment and dollar-cost averaging.

  • Fund Switch Break-Even Calculator

    How many years a lower-cost fund takes to make up the capital gains tax paid to move into it, and the gap between the two choices at a horizon you pick.

  • Modified Dietz Return Calculator

    Your personal rate of return over a period with dated deposits and withdrawals, by the Modified Dietz method, beside the plain end-over-start figure that ignores them.

  • Portfolio Expense Ratio Calculator

    The asset-weighted expense ratio of all your funds together, what it costs in a year, and how that compares with holding everything at one other ratio.

  • CAGR Calculator

    The compound annual growth rate from a start and end value, or from a series of yearly returns, with the gap between the average return and what was earned.

  • Stock Profit Calculator

    Profit or loss on a stock trade after commissions and the tax rate you enter, the return, the annualised return and the sale price that just breaks even.

  • Dividend Yield Calculator

    Dividend yield on today’s price, yield on what you paid, the payout ratio against earnings, and the income your shares bring in each year and each payment.

  • Dividend Reinvestment Calculator

    What reinvesting dividends grows an investment to against taking them as cash, with share price and dividend growth kept separate, and tax on dividends.

  • Dollar-Cost Averaging Calculator

    The shares a fixed amount buys each period, your average cost against the average price, and how it compares with investing everything at the start.

  • Stock Average Calculator

    Your average cost per share across several purchases, what the holding is worth now, and how many more shares at a new price would move the average to a target.

  • Black-Scholes Calculator

    The Black-Scholes value of a European call and put from the share price, strike, time to expiry, risk-free rate, volatility and dividend yield, with d1, d2 and delta.

  • Bond Price Calculator

    What a bond is worth at a market yield: the present value of its coupons and face value, split into clean price and accrued interest between coupon dates.

  • Yield to Maturity Calculator

    The annual return a bond pays if you buy it at today’s price and hold it to maturity, with the effective annual yield and the current yield beside it.

  • Dividend Discount Model Calculator

    The value of a share as the present value of dividends growing at a constant rate forever, the Gordon growth model, and the return implied by a market price.

  • Treasury Bill Calculator

    The price of a US Treasury bill from its discount rate, or its discount rate and investment rate from the price, by the formulas in the Treasury’s auction rules.

  • Tax-Equivalent Yield Calculator

    The taxable yield that would match a tax-free yield after tax at your rate, with a direct comparison against a taxable yield and the tax rate at which they break even.

  • Investment Fee Calculator

    How much an ongoing fee and a sales load cost over time: your balance with and without them, the fees charged, and the growth those fees would have earned.

  • PPF Calculator

    What a Public Provident Fund account grows to over 15 years or more at the current rate, with yearly or monthly deposits and the 5th-of-the-month rule.

  • Sukanya Samriddhi Calculator

    What a Sukanya Samriddhi account for a daughter grows to at maturity after 21 years, from yearly deposits for 15 years at the current rate.

  • NSC Calculator

    The maturity value of a National Savings Certificate after five years at the current rate, with the interest that accrues each year.

  • SCSS Calculator

    The quarterly interest from a Senior Citizens Savings Scheme deposit at the current rate, and what it pays over five years.

  • Post Office MIS Calculator

    The monthly income from a Post Office Monthly Income Scheme deposit at the current rate, for single and joint accounts.

  • Post Office RD Calculator

    The maturity value of a five-year Post Office recurring deposit at the current rate, compounded quarterly as the scheme rules lay down.

  • Kisan Vikas Patra Calculator

    When a Kisan Vikas Patra bought now doubles your money, the date it matures, and the yearly return that doubling works out to.

  • Step-Up SIP Calculator

    What a SIP grows to when you raise the monthly amount every year, next to a SIP that stays the same, with the total invested and the gain.

  • FD Calculator with TDS

    The maturity value of a bank fixed deposit and the tax the bank deducts at source on its interest, with the higher limit for senior citizens.

Small business and investing

Project returns, cash-flow decisions, margins and break-even points.

Energy and utilities

Electricity use, utility bills, vehicles, lighting and battery runtime.

Cars and driving

Fuel cost, gas mileage, road trips, mileage claims, depreciation, what car you can afford, leases, tyre sizes, horsepower and journey times.

Running costs

Fuel cost, gas mileage, road trip cost, mileage reimbursement and depreciation, from your own car's figures.

  • Fuel Cost Calculator

    What a drive costs in fuel from the distance, your car’s economy in mpg, km/L or L/100 km, and the price per gallon or litre, with the cost per mile or km.

  • Gas Mileage Calculator

    Your car’s real fuel economy from a fill-up or several, in mpg, km/L and L/100 km at once, with the cost per mile or km if you add the fuel price.

  • Road Trip Cost Calculator

    The cost of a road trip, fuel plus whatever else you list, one way or return, split between travellers to the cent, with the driving time.

  • Mileage Reimbursement Calculator

    What your mileage claim comes to at the rate you are paid, and how it compares with what the driving actually costs you in fuel and running costs.

  • Car Depreciation Calculator

    What a car will be worth after a number of years at a depreciation rate you choose or derive from a valuation, and what that costs per year and per mile.

Buying and leasing

The car price a monthly payment can buy, its true monthly cost, and a lease payment checked line by line.

  • Car Affordability Calculator

    The most you can spend on a car for a monthly payment you can manage, with your down payment and trade-in, and the true monthly cost once running costs are added.

  • Auto Lease Calculator

    A car lease payment checked line by line: the depreciation and rent charges, the money factor as an APR and back, tax, the total cost and any excess mileage.

  • Cash Back vs Low Interest Calculator

    Compare taking a car maker’s cash back and financing elsewhere with taking its low promotional rate instead.

Specifications

Tyre sizes and speedometer error, horsepower from torque, and speed, distance and time.

  • Tire Size Calculator

    Overall diameter and sidewall from a tyre size such as 225/45R17, and how a different size changes the diameter, what the speedometer reads and the odometer.

  • Horsepower Calculator

    Horsepower and kilowatts from torque and engine speed, or an estimate from quarter-mile trap speed or time, with power at the wheels and power to weight.

  • Speed, Distance and Time Calculator

    Speed, distance or time from the other two, the true average speed over several legs of a journey, and the time a faster speed really saves.

Science and weather

Ohm's law, voltage drop, resistor colour codes, density, molarity, half-life, wind chill, heat index and dew point, from the published equations.

Electronics

Ohm's law for any two of voltage, current, resistance and power, voltage drop along a cable, and resistor colour codes both ways.

  • Ohm’s Law Calculator

    Voltage, current, resistance and power from any two of them, all six combinations, by Ohm’s law and the power relationships.

  • Voltage Drop Calculator

    The voltage lost along a copper or aluminium cable for a given current and run length, single phase, three phase or DC, and what reaches the load.

  • Resistor Colour Code Calculator

    A resistor’s value and tolerance range from its colour bands, or the bands for a value, snapped to the nearest E12, E24 or E96 preferred value.

  • Voltage Divider Calculator

    The output of a two-resistor voltage divider, or the resistor or input voltage that gives the output you need, with the current, the power in each resistor and an optional load.

  • Series and Parallel Resistor Calculator

    The total resistance of up to 12 resistors in series or in parallel, and the current and power they take from a supply voltage if you give one.

  • LED Resistor Calculator

    The series resistor for one LED or a string of them, from the supply voltage and the forward voltage and current on the LED’s datasheet, rounded up to a standard value.

  • AC Power Calculator

    Real, apparent and reactive power for single-phase or balanced three-phase AC from volts, amps and power factor, or the current a load of known watts draws.

  • Lumens to Lux Calculator

    Lux and foot-candles from a light’s lumens spread over an area or in a beam, or the lumens needed for a lux level you choose.

  • AWG Wire Calculator

    The diameter, cross-section and resistance of an American Wire Gauge size, from 4/0 to 40, or the nearest gauge to a diameter or a mm² area.

Physics

Motion with constant acceleration, projectiles and free fall, force, energy, momentum, torque, work and power, pressure, waves, refraction and the Doppler effect.

  • Acceleration Calculator

    Acceleration from a change in velocity over a time, or any two of initial velocity, final velocity, acceleration, displacement and time from the other three.

  • Kinetic Energy Calculator

    The kinetic energy of a moving mass, ½mv², or the mass or speed that gives a kinetic energy, with its momentum.

  • Potential Energy Calculator

    Gravitational potential energy, mgh, or the energy stored in a spring, ½kx², and the mass, height, spring constant or stretch from an energy.

  • Force Calculator

    Force from mass and acceleration by Newton’s second law, F = ma, or the mass or acceleration from the other two, in newtons or pounds-force.

  • Projectile Motion Calculator

    How far, how high and how long a projectile flies from its launch speed, angle and height, with the speed and angle it lands at, ignoring air resistance.

  • Free Fall Calculator

    How long something dropped from a height takes to fall and how fast it lands, or how far it falls in a time, with no air resistance.

  • Torque Calculator

    Torque from a force and a lever arm at any angle, τ = rF sin θ, or the force or arm length needed for a torque, in newton metres or pound-feet.

  • Momentum Calculator

    Momentum from mass and velocity, p = mv, or the mass or velocity from a momentum, plus impulse, FΔt, and the average force behind a change in velocity.

  • Work and Power Calculator

    The work a force does over a distance, W = Fd cos θ, and the average power, P = W ÷ t, or the energy or time from a power.

  • Wavelength Calculator

    Wavelength from frequency, or frequency from wavelength, for light and radio at the speed of light or any wave at a speed you enter, with the photon energy.

  • Pressure Calculator

    Pressure from a force spread over an area, P = F ÷ A, or the force a pressure exerts on an area, or the area a force needs to reach a pressure.

  • Snell’s Law Calculator

    The angle light bends to as it crosses from one material into another, n₁ sin θ₁ = n₂ sin θ₂, or either index or the incident angle, with the critical angle.

  • Doppler Effect Calculator

    The frequency you hear from a moving source or while moving yourself, from the emitted frequency, the speed of sound and each speed and direction.

Chemistry

Density and buoyancy, molarity and dilution, and radioactive or any other exponential half-life.

  • Density Calculator

    Density from mass and volume, or mass or volume from density, with the relative density and whether the object floats and how much of it sits below the surface.

  • Molarity Calculator

    Molarity from a mass of solute, its molar mass and the solution volume, the mass or volume needed for a target molarity, and dilutions by C1V1 = C2V2.

  • Molar Mass Calculator

    The molar mass of a chemical formula from IUPAC standard atomic weights, with brackets and hydrates read correctly, the percentage composition by mass, and moles to grams both ways.

  • Half-Life Calculator

    How much of a decaying quantity remains after a time, or the half-life, elapsed time or starting amount, with the decay constant and mean lifetime.

  • Dilution Calculator

    How much stock to dilute, the final volume, or the strength you end up with, by C1V1 = C2V2 in any concentration unit, with the water to add.

  • Percent Yield Calculator

    Percent yield from the actual and theoretical yield, either yield from the other and a percentage, or the theoretical yield from the limiting reactant and the balanced equation.

  • Buffer pH Calculator

    The pH of a buffer from its pKa and the concentrations of weak acid and conjugate base, or the base-to-acid ratio for a target pH, by the Henderson–Hasselbalch equation.

  • Beer–Lambert Law Calculator

    Absorbance from the molar absorption coefficient, path length and concentration by A = εlc, or any one of them from the others, with absorbance and transmittance converted.

  • Ideal Gas Law Calculator

    Solve PV = nRT for pressure, volume, amount of gas or temperature from the other three, in the units you have, with the molar volume.

  • Grams to Moles Calculator

    Convert between grams, moles and number of particles for any chemical formula or molar mass, using IUPAC atomic weights and the exact Avogadro constant.

  • pH Calculator

    pH and pOH from a hydrogen or hydroxide ion concentration, a strong acid or base, or each other, with [H⁺] and [OH⁻], at 25 °C.

  • Boiling Point at Altitude Calculator

    The temperature water boils at for your altitude or air pressure, and how much lower that is than at sea level.

Weather

Wind chill, heat index and dew point from the published National Weather Service and Magnus equations, in °F or °C.

  • Wind Chill Calculator

    How cold the air feels on exposed skin at a given temperature and wind speed, from the National Weather Service wind chill index, in °F or °C.

  • Heat Index Calculator

    How hot it feels when humidity is added to the air temperature, by the National Weather Service’s own heat index procedure, in °F or °C.

  • Dew Point Calculator

    The dew point from air temperature and relative humidity, or the relative humidity from a dew point, by the Magnus equation, in °F or °C.

  • Sunrise and Sunset Calculator

    Find sunrise, sunset, solar noon and day length for any latitude, longitude and date, on your own clock, with polar day and night stated plainly.

Computing

IPv4 subnets from CIDR notation: network and broadcast addresses, masks, wildcards and usable hosts, by the RFC rules.

  • RAID Rebuild URE Calculator

    The chance a RAID 5 or RAID 6 rebuild reads every surviving drive without an unrecoverable read error, from the error rate on the drive data sheet. A simple model, with its assumptions stated.

  • Subnet Calculator

    Type an IPv4 address in CIDR notation to get its network and broadcast addresses, subnet mask, wildcard mask and usable host range.

Everyday math

Percentages, fractions, ratios, averages and the rest of daily arithmetic.

Everyday Math

Percentages, fractions, ratios, averages, factors, rounding and scientific notation.

  • Booklet Creep Calculator

    How far the centre pages of a saddle-stitched booklet push out past the cover, from the page count and the paper caliper, and how much to shift the pages on any sheet.

  • Percentage Calculator

    Find a percentage of a number, what percent one number is of another, or the whole from a part and its percentage.

  • Percentage Change Calculator

    Measure the increase or decrease from an original value to a new value, and the symmetric percentage difference between them.

  • Fraction Calculator

    Add, subtract, multiply or divide two fractions and reduce the result.

  • Ratio Calculator

    Simplify a two-part ratio and convert each part into a share of the whole.

  • Proportion Calculator

    Solve the fourth value that makes two ratios equal.

  • Average Calculator

    Find the mean, median, mode, range, sum and count of a list of values.

  • Weighted Average Calculator

    Average values that contribute with different weights.

  • Standard Deviation Calculator

    Calculate variance and standard deviation for a population or sample.

  • Rounding Calculator

    Round once to a chosen decimal place or to the nearest multiple, using nearest, floor, ceiling or half to even.

  • Greatest Common Factor Calculator

    Find the largest whole number that divides two integers exactly.

  • Least Common Multiple Calculator

    Find the smallest positive multiple shared by two whole numbers.

  • Scientific Notation Calculator

    Convert a decimal number to normalized scientific and E notation.

  • Scientific Calculator

    Evaluate powers, roots, logarithms and trigonometric functions in degrees.

  • Factor Calculator

    List every positive factor of a whole number and show its prime factorization.

  • Slope Calculator

    Find the slope, rise, run, angle and line equation through two coordinate points.

  • Graphing Calculator

    Graph a quadratic or linear function and inspect its value, vertex and x-intercepts.

  • Aspect Ratio Calculator

    The aspect ratio of a width and height in lowest terms, such as 16:9, or the missing side when you resize an image or screen and keep its shape.

  • Screen Size Calculator

    The width, height and area of a TV, monitor or phone screen from its diagonal size and aspect ratio, or the diagonal from its width and height.

  • PPI Calculator

    Pixels per inch of a screen from its resolution and diagonal, with dot pitch and physical size.

Geometry

Area, perimeter, volume, surface area, triangles and coordinate geometry, from the standard forms.

  • Area Calculator

    The area of a rectangle, square, triangle, circle, ellipse, trapezoid, parallelogram, sector or regular polygon, in any unit.

  • Perimeter Calculator

    The distance around a rectangle, square, triangle, circle, ellipse, trapezoid, parallelogram or regular polygon.

  • Circle Calculator

    Enter any one of a circle’s radius, diameter, circumference or area and get the other three, plus a sector, arc and chord.

  • Triangle Calculator

    Solve a triangle from three sides, two sides and the angle between them, or two angles and a side.

  • Right Triangle Calculator

    Solve a right triangle from two legs, a leg and the hypotenuse, or one side and an angle: every side, both angles and the area.

  • Pythagorean Theorem Calculator

    Find the missing side of a right triangle with a² + b² = c², step by step, spot a Pythagorean triple, or check a corner is square.

  • Volume Calculator

    The volume of a box, cube, cylinder, sphere, cone, pyramid, capsule, hemisphere, frustum, tube or triangular prism, in cubic units, litres and gallons.

  • Surface Area Calculator

    The total, side and base surface area of a box, cube, cylinder, sphere, cone, pyramid, capsule, hemisphere, frustum, tube or triangular prism.

  • Distance Calculator

    The straight-line distance between two points in two or three dimensions, with the midpoint, the change in each coordinate and the slope.

  • Midpoint Calculator

    The point halfway between two points in 2D or 3D, or the missing endpoint when you know one end and the midpoint.

  • Regular Polygon Calculator

    The area, perimeter, apothem, circumradius and angles of a regular polygon from its side, apothem or circumradius.

  • Trigonometry Calculator

    Sine, cosine, tangent, cosecant, secant and cotangent of any angle in degrees or radians, exact on the unit circle, or the angle back from a value.

  • Polar Coordinates Calculator

    Convert a point between Cartesian (x, y) and polar (r, θ) coordinates, with the angle in the right quadrant, in degrees and radians.

Statistics

Averages, spread, percentiles, probability, the normal distribution, confidence intervals, sample sizes, correlation and regression.

  • Mean, Median and Mode Calculator

    The mean, median and every mode of a data set, with its range and quartiles.

  • Variance Calculator

    The sample or population variance of a data set, with the standard deviation, mean, sum of squares and coefficient of variation.

  • Percentile Calculator

    The value at any percentile of a data set, by nearest rank or linear interpolation, or the percentile rank of a value.

  • Probability Calculator

    The probability of two events together or either, a conditional probability by Bayes’ theorem, or k successes in n independent trials.

  • Permutation and Combination Calculator

    How many ways to arrange or choose r items from n, with or without repetition, exactly for large numbers.

  • Z-Score Calculator

    How many standard deviations a value, or a sample mean, lies from the mean, with the probability below, above and in both tails.

  • Normal Distribution Calculator

    The probability below, above, between or outside values of any normal distribution, or the value at a given probability.

  • Confidence Interval Calculator

    A confidence interval for a mean or a proportion, using Student’s t automatically when the population standard deviation is unknown.

  • Margin of Error Calculator

    How far a poll or survey result could be from the truth, at any confidence level, with the correction for sampling much of a small population.

  • Sample Size Calculator

    How many people to survey, or measurements to take, for a chosen margin of error and confidence level, rounded up.

  • Correlation Coefficient Calculator

    Pearson’s r, r squared, the covariance and Spearman’s rank correlation for paired data.

  • Linear Regression Calculator

    The least-squares line of best fit through paired data, with r squared and predictions.

  • Poisson Distribution Calculator

    The probability of exactly k events, at most k, fewer than k, at least k or more than k, when events happen at an average rate λ per interval.

  • Expected Value Calculator

    The expected value, variance and standard deviation of a set of outcomes and their probabilities, with a check that the probabilities add up to 100%.

  • Relative Risk Calculator

    The relative risk and odds ratio from a 2 × 2 table of exposure and outcome, with confidence intervals, the risk in each group and the risk difference.

  • Effect Size Calculator

    Cohen’s d and Hedges’ g for the difference between two group means, from each group’s mean, standard deviation and size, with the pooled standard deviation.

  • Shannon Diversity Index Calculator

    Shannon H, evenness and effective species from counts.

  • P-Value Calculator

    The p-value for a z, t, chi-square or F test statistic, one-tailed or two-tailed, with the areas on each side and a comparison with your significance level.

  • t-Test Calculator

    One-sample, two-sample (Welch or pooled) and paired t-tests from summary statistics: the t statistic, degrees of freedom, p-value and a confidence interval for the difference.

  • Chi-Square Calculator

    Chi-square goodness of fit: compare observed counts with what you expected, and get χ², its degrees of freedom and the p-value.

  • ANOVA Calculator

    One-way analysis of variance from each group’s size, mean and standard deviation: the F statistic, p-value, sums of squares and the ANOVA table.

  • Quartile Calculator

    The first and third quartiles, median, interquartile range, five-number summary and 1.5 × IQR outlier fences of a data set, by linear interpolation, nearest rank or Tukey’s hinges.

  • Odds Calculator

    Convert fractional, decimal and moneyline odds into each other and into implied probability, and see the margin built into a two-way market.

Algebra and numbers

Quadratics, exponents, roots, logarithms, primes, remainders, significant figures, fractions, sequences, matrices and number bases.

  • Quadratic Formula Calculator

    The roots of ax² + bx + c = 0, real or complex, the discriminant and the vertex, computed in a form that stays accurate when one root is tiny.

  • Exponent Calculator

    Any number raised to any power, with whole-number results shown exactly in full, and the cases a plain calculator gets wrong handled properly.

  • Root Calculator

    The square root, cube root or any nth root of a number, the simplified radical form such as 6√2, and the real cube root of a negative number.

  • Logarithm Calculator

    The logarithm of a number in base 10, base 2, the natural base e or any base, with all three common logs side by side and the antilog to check it.

  • Percent Error Calculator

    Percent error = |measured − true| ÷ |true| × 100: how far a measurement is from the true value, whether it was high or low, and the percent difference when neither is true.

  • Prime Number Calculator

    Whether a number is prime, its prime factorisation, how many divisors it has, and the nearest primes either side, for numbers up to a trillion.

  • Modulo Calculator

    The remainder of a division under all three conventions programming languages use, which disagree for negative numbers, and modular powers done exactly.

  • Significant Figures Calculator

    How many significant figures a number has as written, rounding to a set number of them, and the right precision for a sum or a product.

  • Decimal to Fraction Calculator

    A decimal as an exact fraction in lowest terms, repeating decimals included, or as the nearest 16th, 32nd or 64th of an inch with its rounding error.

  • Mixed Number Calculator

    Add, subtract, multiply or divide mixed numbers such as 2 1/2 and 1 3/4, exactly, with the answer as a mixed number, an improper fraction and a decimal.

  • Number Sequence Calculator

    The nth term and the sum of an arithmetic, geometric or Fibonacci sequence, the infinite sum where it exists, and the rule behind a few terms you type.

  • Matrix Calculator

    Multiply, add or subtract two matrices, or find the determinant, inverse, transpose or rank of one, for sizes 2 × 2 to 5 × 5.

  • Binary Calculator

    Convert binary to decimal, hex and octal, or add, subtract, multiply, divide, AND, OR, XOR and shift binary numbers exactly, with two’s complement at 8 to 64 bits.

  • Hex Calculator

    Convert hexadecimal to decimal, binary and octal, read a hex colour as RGB, or add, subtract, multiply, divide, AND, OR, XOR and shift hex numbers exactly.

  • Number Base Converter

    Convert a number between any two bases from 2 to 36, fractions included, with digits the source base does not have named and cut-off fractions flagged.

  • Simplify Fraction Calculator

    Reduce a fraction to lowest terms by dividing by the greatest common factor, with Euclid’s steps, the mixed number and the decimal.

  • Factorial Calculator

    The exact factorial n! of any whole number up to 1,000, every digit shown, with its double factorial n!!, digit count and trailing zeros.

  • Exponential Growth Calculator

    Exponential growth or decay by x₀(1 + r)^t or x₀e^(kt): solve the final amount, starting amount, rate or time, with the doubling time or half-life.

  • Vector Calculator

    Dot product, cross product, magnitudes, the angle between two vectors, their sum and difference, a unit vector and a projection, in 2D or 3D.

  • System of Equations Calculator

    Solve two linear equations in x and y, or three in x, y and z, by Cramer’s rule, with every determinant shown and a plain answer when there is no single solution.

  • Complex Number Calculator

    Add, subtract, multiply, divide or raise complex numbers a + bi to a power, with the modulus, argument, polar form and conjugate of the result.

  • Cubic Equation Calculator

    The three roots of ax³ + bx² + cx + d = 0, real or complex, with the discriminant that says which kind to expect, by the trigonometric and Cardano methods.

  • Big Number Calculator

    Exact arithmetic on whole numbers of up to 79 digits: add, subtract, multiply, divide, raise to a power or take the remainder, with every digit kept.

Cooking and baking

Scale a recipe, swap a baking pan, work out baker's percentages, dough hydration and pizza dough, plan servings, convert oven temperatures and time a roast.

Recipes

Scale a recipe up or down, swap one baking pan for another, and plan how much to cook for a crowd.

  • Recipe Scaling Calculator

    Scale a recipe to more or fewer servings, with amounts written as kitchen fractions, tiny amounts moved to spoons, and eggs kept whole.

  • Baking Pan Conversion Calculator

    Swap one baking pan for another: the new batter depth, how much to scale the recipe, and which way the bake time moves.

  • Serving Size Calculator

    How much food to cook and buy for a crowd from your own amount per person, with extra for seconds and trim divided out properly, or how many portions you have.

  • Cooking Measurement Converter

    Convert cups, spoons, millilitres, grams and ounces, with US, legal and imperial cups kept apart and cups to grams by ingredient from USDA weights.

  • Coffee Ratio Calculator

    Work out how much water goes with your coffee, or how much coffee a given amount of water needs, at the brew ratio you choose.

  • Brine Calculator

    Work out how much salt to weigh for a brine of the strength you choose, as a percentage of the water or of the finished brine.

  • ABV Calculator

    Work out the alcohol content of a homebrew from its original and final gravity, by the common 131.25 rule and by Hall’s more detailed equation.

  • Cooked Weight Calculator

    Convert between raw and cooked weight with a cooking yield, your own or a USDA figure, and split the batch into portions for food logging.

  • Curing Salt Calculator

    Weigh the cure #1 (pink curing salt) for a batch of meat in grams, capped at the USDA’s nitrite limits for ground, dry-cured and brine-cured meat.

Baking

Baker's percentages, dough hydration with a starter, and pizza dough from the size of the pizza.

  • Baker’s Percentage Calculator

    Turn a bread formula into baker’s percentages, flour always 100%, or turn percentages into weights for any batch size, with several flours handled.

  • Bread Hydration Calculator

    The true hydration of a dough with its sourdough starter split into flour and water, or the water to add to reach the hydration you want.

  • Pizza Dough Calculator

    How much dough a pizza of your size needs from a thickness factor, and the flour, water, salt and yeast for the batch, or the thickness factor of a pizza you like.

  • Yeast Converter

    Convert between fresh, active dry and instant yeast by weight, with the packet and teaspoon equivalents, using the yeast makers’ own figures.

  • Candy Making Altitude Calculator

    Lower a candy recipe’s finish temperature for your altitude by how much lower water boils there, from your elevation, a barometer or your own thermometer.

Cooking times and temperatures

Oven temperatures in Celsius, Fahrenheit and gas marks, and when to start a roast to eat on time, with USDA safe temperatures.

  • Oven Temperature Converter

    Convert oven temperatures between Celsius, Fahrenheit and gas marks, see what to set the dial to, and the usual setting for a fan oven.

  • Meat Cooking Time Calculator

    When to put a roast in to eat on time, from its weight, your recipe’s minutes per kilogram or pound and the rest, with the USDA safe internal temperature.

  • Turkey Thawing Calculator

    How long a frozen turkey takes to thaw in the refrigerator or in cold water, and the day to start, using USDA’s published rates.

Tax and shopping

Income tax and take-home pay by country, sales tax, VAT and GST, tips, discounts, unit prices and splitting a bill.

Tax

Sales tax, VAT and GST in both directions, plus capital gains and the effective rate against brackets you enter.

  • Sales Tax Calculator

    Work out the sales tax on a price and the total, from a combined rate or from its state, county, city and district components.

  • Reverse Sales Tax Calculator

    Back the tax out of a total to find the price before tax, and see why subtracting the rate gives the wrong answer.

  • VAT Calculator

    Add or remove VAT at the rate you enter, see the VAT fraction, and work out whether you are payable or reclaimable.

  • GST Calculator

    Add or remove GST at the rate you enter, split into the CGST, SGST, IGST or federal and provincial components an invoice shows.

  • Capital Gains Tax Calculator

    Work out the gain after basis adjustments and the tax at the rate you enter, with losses offset and a loss producing no tax.

  • Effective Tax Rate Calculator

    Enter your own brackets to see total tax, your effective rate and your marginal rate, and why the two are so different.

  • Canada Sales Tax Calculator

    GST, HST, PST or QST on a price in any province or territory, added to a price or taken out of a total.

Shopping

Tips, discounts, unit price comparisons and splitting a bill to the exact cent.

  • Tip Calculator

    Work out the tip, the total and each person’s share, on the pre-tax or post-tax bill, with a round-up option.

  • Discount Calculator

    Work out a sale price after one discount or several stacked, and see what the discounts actually come to combined.

  • Unit Price Comparison Calculator

    Compare packages of different sizes and units by price per unit, including multi-buys, to see which is actually cheaper.

  • Split the Bill Calculator

    Split a bill evenly or by what each person ordered, with tax and tip shared proportionally and the parts always adding up.

  • Dimensional Weight Calculator

    A parcel’s billable weight: the greater of its actual weight and its size divided by your carrier’s divisor.

  • Storage Unit Break-Even Calculator

    The month when what you have paid for a storage unit reaches the value of what is in it, with rent increases, and the total over the stay you plan.

  • Open Bar vs Consumption Bar Calculator

    Compare a per-guest open bar package with a bar billed per drink, with service charge and tax, and find how many drinks per guest make them cost the same.

  • Laundromat vs Washer and Dryer Calculator

    How many months a washer and dryer take to pay for themselves against the laundromat, and what each costs over the years you choose.

  • Gold Price by Purity Calculator

    The gold value of jewellery from its weight and BIS hallmark purity, at the day’s 24K rate, with the making charge.

Income tax

Income tax and take-home pay for salaried employees, country by country, for a named tax year.

Health and fitness

Published equations for body composition, nutrition, training, pregnancy and personal risk estimates.

Body composition

Compare published estimates of body size, body fat, lean mass and surface area.

  • BMI Calculator

    Calculate your body mass index from your height and weight, and see which WHO category it falls in.

  • Body Fat Calculator

    Estimate your body fat percentage from tape measurements using the US Navy circumference method.

  • Lean Body Mass Calculator

    Estimate lean body mass from height and weight using the Boer, James and Hume equations, shown side by side.

  • Ideal Weight Calculator

    See the WHO healthy weight range for your height, alongside what the Devine, Robinson, Miller and Hamwi formulas report.

  • Healthy Weight Range Calculator

    Find the weight range that corresponds to a BMI of 18.5 to 24.9 at your height, and how far any current weight sits from it.

  • Waist-to-Hip Ratio Calculator

    Divide your waist by your hip measurement and compare the result with the WHO thresholds for fat distribution.

  • Body Surface Area Calculator

    Calculate body surface area with the Mosteller, Du Bois, Haycock, Gehan-George and Boyd equations, and see how far apart they are.

  • Army Body Fat Calculator

    Estimate body fat with the US Army’s one-site tape equation, from weight and the abdomen measured at the navel.

  • Height Predictor Calculator

    Estimate a child’s target adult height range from both parents’ heights, using the mid-parental method of Tanner and colleagues.

  • FFMI Calculator

    Work out your fat-free mass index from weight, height and a body fat estimate, and the height-normalised figure from Kouri and colleagues.

Nutrition and energy

Estimate resting energy, activity energy, nutrient ranges and water intake from published guidance.

  • BMR Calculator

    Estimate your basal metabolic rate with the Mifflin-St Jeor, Harris-Benedict and Katch-McArdle equations, side by side.

  • TDEE Calculator

    Estimate total daily energy expenditure as a range, using the FAO/WHO/UNU physical activity level bands.

  • Calorie Calculator

    Turn a weight goal and a rate you choose into a daily calorie target, with the limits of that arithmetic stated.

  • Macro Calculator

    Convert a daily calorie figure into grams of protein, carbohydrate and fat, and check the split against the published AMDR bands.

  • Protein Intake Calculator

    Work out the adult protein RDA for your body weight, and cross-check it against the published AMDR range.

  • Carbohydrate Intake Calculator

    Turn a share of your daily energy into grams of carbohydrate, against the AMDR band and the 130 gram RDA.

  • Fat Intake Calculator

    Turn a share of your daily energy into grams of fat, against the AMDR band and the saturated fat reference.

  • Water Intake Calculator

    See the published adequate intake of total water, how much of it comes from drinks, and how much comes from food.

  • Alcohol Macro Calculator

    Work out the grams of alcohol and the calories in a drink, and how to log them as carbohydrate or fat in an app that has no alcohol entry.

Fitness and training

Estimate exercise energy, strength, heart-rate zones, running pace and aerobic fitness.

  • Calories Burned Calculator

    Estimate the energy an activity uses from its published MET value, your weight and how long you spent.

  • One Rep Max Calculator

    Estimate your one-rep max from a submaximal set with the Epley, Brzycki, Lombardi and O’Conner equations.

  • Target Heart Rate Calculator

    Work out a training heart rate zone from the Tanaka maximum and the Karvonen reserve method, with 220 minus age shown for comparison.

  • Running Pace Calculator

    Turn a distance and a finish time into pace and speed, with Riegel equivalent times over the standard race distances.

  • VO2 Max Calculator

    Estimate VO2 max from the Cooper twelve-minute run, the Rockport one-mile walk or the resting heart rate ratio.

  • Steps to Miles Calculator

    Turn a step count into miles or kilometres using your own measured step length, or work out how many steps a distance takes.

  • Bike Gear Ratio Calculator

    Work out a bicycle gear ratio from the chainring and cog, and with your wheel size, gear inches, development per pedal turn and speed at a cadence.

  • Wilks Calculator (IPF GL Points)

    Score a powerlifting total or bench press against bodyweight with the IPF GL formula, the points system the IPF uses in place of Wilks.

  • Cycling Power Calculator

    Estimate the power needed to ride at a steady speed from air drag, rolling resistance, bearing friction and gradient, using the Martin et al. road cycling model.

  • Marathon Fuel Calculator

    Turn an hourly carbohydrate target into the number of gels or chews to carry for your race time, and how often to take one.

  • Sweat Rate Calculator

    Work out how much you sweat per hour from your weight before and after exercise, what you drank and the time, with sodium lost if you know your sweat sodium.

Pregnancy

Date pregnancy milestones and compare weight gain with published guideline ranges.

  • Due Date Calculator

    Estimate a due date from a last menstrual period, a conception date or an IVF transfer, using the ACOG method.

  • Ovulation Calculator

    Estimate ovulation and the fertile window by counting back from your next expected period, not forward from your last.

  • Conception Date Calculator

    Work backwards from a due date, a last period or a gestational age to the window in which conception is likely to have happened.

  • Pregnancy Weight Gain Calculator

    See the IOM recommended total weight gain for your pre-pregnancy BMI, and what that implies by a given week.

  • Period Calculator

    Estimate when your next six periods start from the first day of your last one and your average cycle length.

Health risk

Estimates from named published equations, for context rather than diagnosis.

  • Blood Alcohol Calculator

    See what NHTSA’s blood alcohol method estimates from what you entered, and how wide the range around that estimate really is.

  • eGFR Calculator

    See the estimated glomerular filtration rate the race-free CKD-EPI 2021 equation gives for a creatinine result, age and sex. An estimate, not a diagnosis.

  • A1C Calculator

    Convert an A1C result to estimated average glucose in mg/dL or mmol/L, or an average back to A1C, with the ADAG equation, and A1C between % and mmol/mol.

  • Blood Sugar Converter

    Convert blood glucose between mg/dL and mmol/L using the molar mass of glucose, and see how far the rounded factor of 18 moves the answer.

Sports statistics

Batting average, OBP, SLG and OPS, ERA and WHIP, Elo and FIDE rating changes, NFL passer rating and bowling scores, by each sport's own rules.

  • Batting Average Calculator

    Work out a batting average, on-base percentage, slugging percentage and OPS from at bats, hits, walks and extra-base hits, by rule 9.21 of the Official Baseball Rules.

  • ERA Calculator

    Work out a pitcher's earned run average and WHIP from earned runs, hits, walks and innings pitched, with innings typed the box-score way, 6.2 for 6⅔.

  • Elo Rating Calculator

    Work out the expected score and the rating change after one game, by the Elo formula or by the FIDE rating regulations with their table and 400-point rule.

  • Passer Rating Calculator

    Work out an NFL passer rating from attempts, completions, yards, touchdowns and interceptions, with each of the formula's four capped parts shown.

  • Bowling Score Calculator

    Type a ten-pin game the way a score sheet marks it, X for a strike and / for a spare, and get the score frame by frame under the USBC rules.

  • Golf Handicap Calculator

    Work out a World Handicap System handicap index from your scores or score differentials, and the course handicap an index gives on a set of tees.

Date and time

Calendar differences, business days, durations and time zones.

Real estate investing

Rental income, cap rate, cash flow, loan coverage and cash return on a property.

Buying and selling a home

Closing costs, cash to close, seller proceeds, tax proration and equity.

Salary and pay

Pay across periods, overtime, raises, bonuses and time worked.

Education

Grades, GPA, attendance, degree progress and study planning.

Conversions

Height in feet and centimetres, Roman numerals, data storage in GB and GiB, fuel economy between mpg and L/100 km, and angles in degrees and radians.

Size conversions

Height, shoe, ring and clothing sizes, converted through the body measurement each size stands for, using the ISO, JIS and EN standards that define them.

  • Height Converter

    Convert a height between feet and inches and centimetres, exactly, written as 5 ft 10 in rather than 5.83 ft, with the inches never rounding to 12.

  • Shoe Size Converter

    Convert a foot length or a shoe size between US, UK, EU and Mondopoint sizes using the ISO 19407 conversion, with the nearest size and the sizes either side.

  • Ring Size Converter

    Find a ring size from the inside circumference or diameter, exactly as ISO 8653 defines it, and convert between ISO and Japanese ring sizes.

  • Clothing Size Converter

    Turn your bust or chest, waist and hip measurements into the EN 13402 size bands clothes are designated by, with the band each measurement falls in and the sizes either side.

  • Land Area Unit Converter (India)

    Convert Indian land units, bigha, katha, guntha, cent, gaj, marla and kanal, to square feet, square metres, acres and hectares, using official state figures.

Notation conversions

Roman numerals, data storage prefixes, fuel economy measures and angle units: conversions where the notation itself is the hard part.

  • Roman Numeral Converter

    Convert numbers to Roman numerals and back, from 1 to 3999, with each numeral checked against the rules and a rejected one told which rule it breaks.

  • Data Storage Converter

    Convert between bits, bytes, decimal GB and TB and binary GiB and TiB, see why a 1 TB drive shows as 931 GB, and how long a file takes at a given speed.

  • Fuel Economy Converter

    Convert fuel economy between US mpg, imperial mpg, km per litre and litres per 100 km, with the cost per mile and km when you add a fuel price.

  • Degrees and Radians Converter

    Convert angles between degrees, radians, gradians and turns, with radians given exactly as a multiple of π, such as π/6 for 30°, as well as in decimals.

  • Military Time Converter

    Convert a 12-hour AM or PM time to military and 24-hour time, or a military time such as 1430 back to the 12-hour clock.

  • Unix Timestamp Converter

    Convert a Unix timestamp in seconds or milliseconds to a UTC date and time, or a UTC date and time back to a Unix timestamp.

  • Fraction to Decimal Calculator

    Write a fraction or mixed number as an exact decimal, with the repeating digits marked, and rounded to the number of places you choose.

  • Color Converter

    Convert a colour between hex, RGB and HSL notation, using the conversions in the CSS Color Module Level 4 specification.

  • DMS Converter

    Convert latitude, longitude or any angle between degrees, minutes and seconds and decimal degrees, with degrees and decimal minutes as well.

  • Lakh and Crore Converter

    Write any number the Indian way, in lakh and crore with Indian commas and in words, next to the international million and billion form, with cheque wording.

Hobbies, crafts and pets

Quilt setting triangles, fabric yardage at a new width, curtain pleats, leather thread, dye baths and mould rubber, plus feed and running costs for dogs, horses and backyard hens, and darkroom, camping and Morse code timing.

Crafts and sewing

Quilting, sewing, leatherwork, soap, dyeing and mould making: yardage, pleats, thread, batch sizes and dye weights from your own pattern and product figures.

  • Setting Triangle Calculator

    The squares to cut for the side and corner setting triangles of an on-point quilt, how many of each, and the size of the finished top.

  • Fabric Width Conversion Calculator

    Fabric to buy when your fabric is a different width from the pattern’s, rounded up to 1/8 yard.

  • Curtain Pleat Calculator

    Pleat size and spacing for pinch-pleated curtains, the fabric widths and cut drops they need at your fullness, and the total fabric with any pattern repeat.

  • Saddle Stitch Thread Calculator

    Thread to cut for a hand saddle stitch in leather, from seam, thickness and stitch spacing.

  • Silicone Mold Calculator

    How much silicone mould rubber a poured block mould takes, by weight, from the mould box, the model and the product’s specific gravity, with part A and part B.

  • Soap Mold Batch Calculator

    Oils to fill your soap mould, from its size and your recipe. It does not calculate lye.

  • Belt Blank Calculator

    How long to cut a leather belt strap for your size, where to punch the holes, and how many belts a side of leather gives.

  • Dye Depth of Shade Calculator

    Dye powder for a depth of shade, the stock solution to measure and the dye bath water.

Pets and backyard animals

How long a bag of dog food lasts, hay for a horse by body weight, and what backyard eggs really cost, from your own feed, prices and animals.

  • Egg Cost Calculator

    What your backyard eggs cost in feed: the cost per egg and per dozen from your flock, its feed and the eggs you collect.

  • Dog Food Bag Calculator

    How long a bag of dog food lasts, how many cups are in it, and what feeding costs a day, a month and a year.

  • Horse Hay Calculator

    How much hay a horse eats a day and how many bales to buy for the winter or any number of days, with storage and feeding waste allowed for.

Hobbies and outdoors

Darkroom print exposure after a size change, camping stove fuel left and needed, and Morse code timing from words per minute.

  • Fuel Canister Calculator

    How much gas is left in a part-used backpacking stove canister, and how much fuel and how many canisters to bring for a trip.

  • Enlarger Exposure Calculator

    The new darkroom exposure time after raising or lowering the enlarger for a bigger or smaller print, or after a change in stops.

  • Morse Code Timing Calculator

    Dit, dah and gap lengths in milliseconds for any Morse code speed, the speed from a dit length, and Farnsworth spacing for learning.

Home and construction

Materials and quantities for a building or renovation job, with waste included.

Concrete

Slabs, footings, columns and post holes: how much concrete, and how many bags.

Masonry

Brick, block and retaining wall quantities for a given wall area.

Paint and drywall

Paint volume and drywall sheets for rooms and walls.

  • Paint Calculator

    Work out how much paint a room needs, with doors and windows taken out.

  • Drywall Calculator

    Work out how many sheets of drywall a room needs, openings taken out.

  • Wallpaper Calculator

    Estimate wallpaper rolls from wall width, drop height, roll size and pattern repeat.

  • Insulation Calculator

    Estimate insulation packs from several wall or ceiling areas and the coverage on the pack.

  • Siding Calculator

    Estimate siding cartons from wall areas, openings and the coverage on each carton.

  • Plaster and Render Calculator

    Estimate wet plaster or render volume and bags from area, thickness and product yield.

  • Drywall Mud and Tape Calculator

    Joint compound, paper tape and screws for a Level 4 or 5 drywall finish, from the sheet count and manufacturer data-sheet rates.

  • Caulk Calculator

    How many tubes of caulk or sealant a job takes, from the length of the joints and the size of the bead, and how far one cartridge goes.

Flooring and tile

Tiles, boxes, grout and flooring for a floor or wall area.

  • Tile Calculator

    Work out how many tiles and boxes a floor or wall needs, grout joints included.

  • Flooring Calculator

    Work out how many boxes of flooring a room or set of rooms needs.

  • Grout Calculator

    Work out how much grout a tiled area needs, by weight.

  • Carpet Calculator

    Estimate linear carpet length for a rectangular room from the available roll width.

  • Epoxy Floor Coating Calculator

    Estimate epoxy coating kits from floor area, coats and the coverage on the product label.

  • Thinset Calculator

    How many bags of thinset mortar to buy for a tile floor or wall, from the area and the trowel notch, using a maker’s published coverage per bag.

  • Self-Leveling Underlayment Calculator

    How many bags of self-leveling underlayment a floor takes at an even depth or across a sloping floor, from the yield printed on the bag.

  • Tile Leveling Clip Calculator

    How many tile leveling clips and wedges a floor takes, from the room and tile sizes and the spacing between clips along each joint.

Landscaping

Gravel, mulch, topsoil and pavers by volume, weight or bag.

  • Gravel Calculator

    Work out the volume and weight of gravel for a driveway, path or base layer.

  • Mulch Calculator

    Work out how many bags or cubic yards of mulch a bed needs, including round beds and rings around trees.

  • Paver Calculator

    Work out how many pavers a patio needs, plus the base and bedding sand under them.

  • Topsoil Calculator

    Work out how much topsoil a lawn or bed needs, in yards, tons or bags.

  • Sand Calculator

    Calculate sand volume and bags for a rectangular area at a chosen depth.

  • Sod Calculator

    Estimate how many sod rolls a lawn needs from its area and the supplier’s roll size.

  • Asphalt Calculator

    Estimate compacted asphalt volume and weight using a supplier-provided mix density.

  • French Drain Gravel Calculator

    Estimate gravel volume and bags for a drain trench after subtracting the pipe.

  • Plant Spacing Calculator

    How many plants fit a bed at the spacing on the label, in square rows or staggered triangular rows, which fit about 15% more.

  • Fertilizer Calculator

    How much fertiliser to spread for a nitrogen, phosphorus or potassium rate, from the N-P-K on the bag, with all three nutrients it delivers and the bags to buy.

  • Raised Bed Soil Calculator

    How much soil mix fills a raised bed, measured inside its walls, split into compost, topsoil and aeration, with bags to buy and room for settling.

  • Sprinkler Coverage Calculator

    How many sprinkler heads cover a lawn at head-to-head spacing, their precipitation rate, and how long to run the zone.

  • Firewood Cord Calculator

    How many cords are in a stack of firewood, what share of a cord a face cord really is, and how long a stack you need for the cords you want.

  • Grass Seed Calculator

    How much grass seed to buy for a new lawn or for overseeding, from the lawn’s area and the seeding rate printed on the bag, with the bags it takes.

  • Pond Liner Calculator

    What size of liner a garden pond needs from its longest length, widest width and deepest point, with an overlap at the edges, and roughly how much water it holds.

  • Driveway Sealer Calculator

    How many pails of asphalt driveway sealer to buy for the area and coats, from the coverage printed on the pail, per gallon or per pail.

  • Hoop House Calculator

    The length of each hoop, how many hoops, and the size of plastic sheet for a round-topped hoop house or high tunnel, from its width, height and length.

  • Compost Calculator

    How much brown material to mix with green for a target carbon-to-nitrogen ratio, or the C:N and moisture of a mix, by Cornell’s two-material method.

  • Fire Glass Calculator

    How many pounds of fire glass a round or rectangular fire pit or fireplace takes for the depth you want, and how many bags to buy.

  • Ice Melt Calculator

    How much ice melt or rock salt a driveway, walk and steps take at the rate printed on the bag, and how many bags to buy for a storm or a winter.

  • Drip Irrigation Run Time Calculator

    How long to run a drip zone to give each plant, or a whole bed, the water it needs.

  • Waterfall Pump Flow Calculator

    The pump flow a waterfall or pond spillway needs for a trickle, a sheet or a heavy fall.

Roofing

Roof pitch, roof area and shingle bundles.

  • Roof Pitch Calculator

    Convert between roof pitch, angle and rise over run, and get the rafter length.

  • Roofing Shingle Calculator

    Work out the roof area and how many bundles of shingles it takes to cover it.

  • Gutter Calculator

    Count stock gutter sections and downspouts for one or more identical straight runs.

  • Roof Area Calculator

    The surface area of a gable, hip, shed or gambrel roof from the building’s footprint, overhang and pitch, in square feet or metres and roofing squares.

  • Roofing Calculator

    From the building’s size, overhang, pitch and roof type to the roof area, roofing squares and bundles of shingles to buy, with an optional installed cost.

  • Metal Roofing Calculator

    How many metal roof panels a gable or shed roof takes and how long to cut them, from the building, the pitch, the overhangs and the panel’s coverage width.

  • Ice and Water Shield Calculator

    Rolls of ice and water shield for your eaves, from their length, the pitch and how far up the roof it must reach.

Decking and fencing

Deck boards, fence posts, rails and pickets.

  • Fence Calculator

    Count the posts, rails and pickets a run of fence needs.

  • Deck Board Calculator

    Count the deck boards a deck needs, in rows, linear feet and boards.

  • Baluster Calculator

    Count evenly spaced balusters from an opening, baluster width and permitted clear gap.

  • Deck Joist and Beam Calculator

    Count joists, beam lines and beam members from an existing deck framing layout.

  • Deck Stain Calculator

    How much stain a deck or fence takes, counting the floor, both faces of the railing and the stairs, from the coverage on the can and the number of coats.

Lumber and carpentry

Board feet and stair dimensions.

  • Board Foot Calculator

    Convert lumber dimensions into board feet, and price the order.

  • Stair Calculator

    Work out risers, treads, total run and stringer length from a total rise.

  • Wainscoting Calculator

    Count pre-sized wainscoting panels from the net wall run and actual panel width.

  • Crown Moulding Calculator

    Estimate crown moulding, baseboard or door casing stock from a room perimeter, a measured run or the openings to be cased.

  • Feet and Inches Calculator

    Add, subtract, multiply or divide lengths written in feet, inches and fractions, with the answer read to the nearest sixteenth of an inch.

  • Framing Calculator

    Count the studs for a wall at 16 or 24 inches on centre, with the extra studs your corners and openings take, and the plate stock to buy.

  • Plywood Calculator

    How many sheets of plywood or OSB cover a floor, a wall or a pitched roof, with openings taken off and the roof slope allowed for.

  • Board and Batten Calculator

    Boards and battens for a wall of vertical board and batten siding, from the wall, board width, gap and openings.

  • Shiplap Calculator

    How many shiplap boards cover a wall or ceiling, from its area, the exposed face of each board and the board length.

  • Epoxy Resin Calculator

    How much epoxy resin a river table, casting or countertop pour takes, how many kits to buy, and how much resin and hardener to measure out.

  • Miter Angle Calculator

    The miter saw setting for a frame with any number of sides or for any corner, with the cut angle and the inside length of each frame piece.

  • Arch Calculator

    The radius, arc length and centre point of a segmental arch from its span and rise, and the height of the curve at any point for laying it out.

  • Spiral Staircase Calculator

    The riser height, number of treads, tread angle and going of a spiral staircase from its floor-to-floor rise, rotation and diameter.

  • Cabinet Door Calculator

    The size to make overlay or inset cabinet doors from the opening, the overlay or reveal, and the gap between a pair of doors.

  • Lumber Weight Calculator

    How much a board, a stack of studs or a load of hardwood weighs, from its size, the species and how wet the wood is, using the USDA Wood Handbook.

  • Kerf Bending Calculator

    How far apart to cut the kerfs to bend a board or sheet to a radius, how deep to cut them, and how many cuts the curve takes.

Home systems

Pool volume and chlorine, a rough heating and cooling estimate, water heater sizing and rainwater harvesting.

  • Pool Volume Calculator

    How many gallons or litres a pool holds, for rectangular, round, oval and kidney pools, with a constant depth, a slope or a flat-slope-flat floor.

  • Pool Chlorine Calculator

    How much chlorine product raises a pool’s free chlorine to your target, from its volume and the available chlorine on the product label.

  • BTU Calculator

    A rough range for the heating or cooling a room needs, in BTU per hour, tons and kilowatts, from its floor area and your own BTU-per-square-foot figures.

  • Water Heater Sizing Calculator

    The first-hour rating a tank needs for your busiest hour, or the power a tankless heater needs.

  • Rainwater Harvesting Calculator

    How much rain a roof collects, and the tank to last a dry spell.

  • Pipe Volume Calculator

    How much water a pipe holds, in gallons or litres, from its inside diameter and length, with the weight of that water.

  • CFM Calculator

    Air changes per hour from a fan’s airflow and the room’s size, or the CFM a fan must move for the air changes you are aiming for.

  • Flow Rate Calculator

    A tap, hose or pump’s flow in gallons or litres a minute from a bucket test, or from the water’s speed in a pipe, and how long it takes to fill something.

  • Rolling Offset Calculator

    The travel and setback of a rolling pipe offset from its rise and roll, for 45, 22½, 60 or 11¼ degree fittings or any other angle.

  • Well Volume Calculator

    How much water is standing in a drilled well, from the casing’s inside diameter, the well depth and the depth to the water.

  • Pool Pump Run Time Calculator

    How many hours a day to run a pool pump for the turnovers you want, or the flow needed for a set run time.

  • Pool Heat-Up Time Calculator

    How long a pool or hot tub heater takes to raise the water to the temperature you want, with the gas or electricity it uses and the cost.

  • Water Softener Sizing Calculator

    The grain capacity a whole-house water softener needs for your household, hardness and iron.

Area and volume

Square footage, cubic yards and slope, for any shape.

  • Slope and Grade Calculator

    Convert between rise and run, percentage grade, angle and ratio.

  • Square Footage Calculator

    Work out the area of a room or plot, or what a run of boards covers, in square feet, yards, metres or acres.

  • Cubic Yard Calculator

    Convert a length, width and depth into cubic yards, feet, metres and litres.

  • Tank Volume Calculator

    How much a cylindrical, rectangular or capsule tank holds, standing or lying down, and how much is in it at a measured liquid depth.

  • Aquarium Calculator

    How many gallons or litres a rectangular fish tank holds, what the water weighs, and with the glass thickness, what the glass and the full tank weigh.