FIRE Calculator: Financial Independence Number and Timeline
This FIRE calculator shows your FIRE number and how many years until you can retire early. Enter your income, spending and savings, then set your own return, inflation and withdrawal rate. Results are in today's dollars.
A FIRE calculator estimates when you can reach financial independence and retire early. It finds your FIRE number, the invested amount whose withdrawals cover your yearly spending, by dividing annual spending by a withdrawal rate. It then projects how many years your savings and contributions need to get there at an inflation-adjusted return.
How this FIRE calculator works
Everything is worked out in today's dollars, so the result is not flattered by inflation.
- FIRE number = annual spending in retirement ÷ withdrawal rate. At 4% that is 25 times your spending.
- Real return = (1 + expected return) ÷ (1 + inflation) − 1. A 7% return with 3% inflation is a 3.88% real return, not 4%.
- Years to FIRE come from the future value of an annuity: savings × (1 + r)n + yearly saving × ((1 + r)n − 1) ÷ r = FIRE number, solved for n, where r is the real return.
Yearly saving is income minus current spending, added at the end of each year and assumed to rise with inflation. If you enter a desired monthly income in retirement, the FIRE number is built on that figure instead of your current spending. Taxes on withdrawals, pensions and Social Security are not modelled.
FIRE calculator example: $40,000 a year of spending
Press Load Example to run it: age 30, $80,000 after-tax income, $40,000 spending, $50,000 invested, 7% return, 3% inflation, 4% withdrawal rate.
| Step | Working | Result |
|---|---|---|
| FIRE number | $40,000 ÷ 0.04 | $1,000,000 |
| Yearly saving | $80,000 − $40,000 | $40,000 (50% savings rate) |
| Real return | 1.07 ÷ 1.03 − 1 | 3.88% |
| Years to FIRE | ln(78,835 ÷ 41,942) ÷ ln(1.03883) | 16.6 years |
| FIRE age | 30 + 17 (next full year) | 47 |
| FIRE number in that year's dollars | $1,000,000 × 1.0316.6 | $1,631,669 |
| Yearly spending in that year's dollars | $40,000 × 1.0316.6 | $65,267 |
Years to FIRE by savings rate
Your savings rate matters more than your salary, because spending less both raises what you save and lowers the number you need. Starting from zero with a 5% real return and a 4% withdrawal rate, the calculator gives:
| Savings rate | FIRE number (multiple of income) | Years to FIRE |
|---|---|---|
| 10% | 22.5× | 51.4 |
| 25% | 18.75× | 31.9 |
| 50% | 12.5× | 16.6 |
| 75% | 6.25× | 7.1 |
To check a row, enter income 100,000, spending 100,000 minus the savings, 0 saved, 5% return and 0% inflation.
The 4% rule: where it comes from and what it does not promise
The 4% default comes from two studies of past US market returns. In 1994 financial planner William Bengen found that a first-year withdrawal of 4%, raised with inflation afterwards, had never emptied a portfolio in under 33 years (Bengen, Journal of Financial Planning). In 1998 three Trinity University professors tested withdrawal rates over payout periods of 15 to 30 years using 1926 to 1995 returns and concluded that 3% and 4% rates were extremely unlikely to exhaust a stock and bond portfolio (Cooley, Hubbard and Walz, AAII Journal).
It is a historical rule of thumb, not a guarantee. Both studies look backwards, and the Trinity study stops at 30 years, which is shorter than many early retirements. Bengen's own figures showed 3% to 3.5% lasting at least 50 years in every past case, so a lower rate is a reasonable choice for a long retirement. Change the withdrawal rate box to see what that costs you:
| Withdrawal rate | FIRE number | For $40,000 a year |
|---|---|---|
| 3% | 33.3 × spending | $1,333,333 |
| 3.5% | 28.6 × spending | $1,142,857 |
| 4% | 25 × spending | $1,000,000 |
| 5% | 20 × spending | $800,000 |
Financial independence, early retirement and the FIRE variants
Financial independence is the point where your investments can pay for your spending; retiring early is one thing you can do with it. Many people who reach it keep working on their own terms. Lean FIRE aims for a small budget (see the Lean FIRE calculator), Fat FIRE for a generous one, and Barista FIRE covers part of the bills with part-time work. Coast FIRE is a different question, whether what you have already invested will grow to a normal-age retirement target without further saving, and has its own Coast FIRE calculator.
Results are estimates for planning, not financial advice or a prediction of market returns. Last updated: October 2026.
Frequently Asked Questions
What is a FIRE calculator?
A FIRE calculator works out your FIRE number, the invested amount that can cover your yearly spending, and how many years it will take you to reach it. This one divides your annual spending by a withdrawal rate you choose, then projects your savings and contributions forward using a return adjusted for inflation.
What is a FIRE number?
Your FIRE number is your annual spending in retirement divided by your withdrawal rate. At a 4% withdrawal rate it is 25 times your spending, so $40,000 a year needs $1,000,000 invested. At 3.5% the same spending needs $1,142,857. It is a planning target in today’s dollars, not a guaranteed amount.
What is the 4% rule?
The 4% rule says you withdraw 4% of your portfolio in the first year of retirement and raise that dollar amount with inflation each year. It comes from William Bengen’s 1994 study and the 1998 Trinity study, which tested past US market returns over periods of up to 30 years. It is a historical rule of thumb, not a guarantee, and early retirees with longer horizons often use 3% to 3.5%.
How much do I need to save to retire early?
Divide the amount you want to spend each year by your withdrawal rate. At 4% you need 25 times your annual spending invested; at 3% you need about 33 times. How fast you get there depends mostly on your savings rate: starting from zero with a 5% real return, saving 50% of income takes about 17 years and saving 25% takes about 32 years.
How does inflation change my FIRE number?
Inflation raises the dollar amount you will need by the time you get there. At 3% inflation a $1,000,000 target becomes about $1,631,669 in 16.6 years. This calculator keeps everything in today’s dollars and uses a real return, (1 + return) divided by (1 + inflation) minus 1, so the years to FIRE already allow for rising prices.
Is a 7% return realistic?
Nobody can promise it. The Trinity study reports that large-company US stocks compounded at roughly 10.5% a year and long-term corporate bonds at 5.7% from 1926 to 1995, before inflation. A 7% assumption for a mixed portfolio sits between those figures, but future returns can be lower, so test a few values and see how much your FIRE date moves.
Is financial independence the same as early retirement?
No. Financial independence means your investments can cover your spending, so paid work becomes optional. Retiring early is one choice you can make at that point. Many people who reach their financial independence number keep working part-time or on projects they choose. The calculator gives the same number either way.
What is Coast FIRE?
Coast FIRE means you have already invested enough that growth alone should reach a normal-age retirement target, so you only need to earn enough to cover current spending. It is a different calculation from the FIRE number on this page, which assumes you keep saving until work is optional.