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.
Result
Enter withdrawal rate to see the result.
https://calcgallery.com/retirement-planning/fire-number-calculator/
Results are arithmetic on the returns, rates and horizons you enter, not a forecast and not investment, tax or retirement advice. The site supplies no expected return, inflation rate, contribution limit, tax rate or withdrawal rate. Real returns vary from year to year, and fees, taxes and the order of returns all change the outcome. Check anything that matters with a qualified adviser. Read the full disclaimer
How to use the FIRE Number Calculator
- Enter what you expect to spend each year once you stop working, in today's money, and the withdrawal rate you want to plan around.
- Enter your savings, your income after tax, what you spend now, and the real return you want to assume.
- Read your FIRE number and how many years it takes at your current savings rate.
Where the number comes from
The FIRE number is your yearly spending divided by a withdrawal rate. It is the portfolio that could fund that spending at that rate. Everything is in today’s money, which is why the return you enter should be a real return, after inflation.
Savings rate dominates
The years to financial independence depend far more on how much of your income you save than on the return. Starting from nothing at a 5% real return, saving half your income gets there in about 16.6 years; saving a quarter takes about 31.9. Doubling the savings rate roughly halves the time, because it both adds more and lowers the spending you need to replace. No plausible change in return does as much.
How the years are worked out
Savings grow at the real return, with a year’s savings added at the end of each year, until they reach the target. That has a closed form: with P saved, S saved a year and a return i, the target T is reached after ln((T + S/i) ÷ (P + S/i)) ÷ ln(1 + i) years. If you save nothing and your savings cannot grow to the target, the page says so.
What is not modelled
Taxes on withdrawals, healthcare before retirement age, the order of returns, and the fact that spending changes over a long retirement. The safe withdrawal rate calculator shows how long a portfolio lasts at a given withdrawal.
With your numbers
- FIRE number = $40,000.00 ÷ 4% = $1,000,000.00
- Saving $35,000.00 a year, 38.9% of income, from $100,000.00 at 5%
- Years = 15.45
Quick reference
On your withdrawal rate and real return. Not a forecast, and no withdrawal rate is recommended.
| Example | FIRE number |
|---|---|
| 40,000 at 4%, saving 35,000 a year | $1,000,000.00 |
| 40,000 at 3% | $1,333,333.33 |
| 40,000 at 5% | $800,000.00 |
| 60,000 at 4% | $1,500,000.00 |
| Saving half of 80,000 from nothing | $1,000,000.00 |
| Saving a quarter of 80,000 from nothing | $1,500,000.00 |
| Spending all income | $1,000,000.00 |
Common questions about the FIRE Number Calculator
- What is the 4% rule?
- A 1994 study by William Bengen looked at US stock and bond returns from 1926 and found that withdrawing 4% of a portfolio in the first year, then the same amount raised with inflation, would have lasted at least 30 years in every historical period he tested. It is one study of one country's past returns over 30-year periods. This page does not default to it; choose your own rate.
- Is 4% still safe?
- Nobody can promise that, which is why the rate is yours to choose. Retiring early means the money must last longer than the 30 years the study tested, and future returns may differ from past ones. A lower rate means a bigger target and more margin.
- What is coast FIRE?
- The amount that, left alone at your assumed return, grows to your FIRE number by the age you would stop working anyway. Once you have it, you only need to earn enough to cover your spending. With a 1,000,000 target, 25 years to go and a 5% real return, the coast number is about 295,000.
- How much do I need to retire early?
- Your yearly spending divided by the withdrawal rate you trust. At 40,000 a year, that is 1,000,000 at 4%, 1,333,333 at 3% and 800,000 at 5%. The spending figure is the one you control most.