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.
Shop arithmetic is simple and the traps in it are not. Two 20% discounts are not 40% off, they are 36%, because the second is taken from what the first left; two 50% discounts do not make anything free. A larger box is not automatically cheaper, and the only way to know is to put both packages into the same unit, which is what the comparison here does even when one is in ounces and the other in kilograms. A tip can be taken before or after tax and both are common, so it is a choice you make rather than one made for you. Splitting a bill leaves cents that do not divide, and those cents are distributed here one at a time so the shares add up to the total exactly instead of landing a penny short. No tipping percentage on this site is presented as the correct one. Conventions vary by country and by service, and that is not arithmetic.