FIRE Calculator
How much you need to stop working, and how many years it takes to get there.
Good to know. Spending less counts twice: it lowers the target and raises what you save toward it.
Not financial advice. Uses only the numbers and rates you enter — no live data.
How it works
In plain words
Your FIRE number is what you spend in a year divided by the withdrawal rate: 25 times your spending at 4%. The calculator then grows what you have invested, plus what you save each month, at the return after inflation, until it reaches that number.
The formula
FIRE number = yearly spending ÷ withdrawal rate Each month: invested = invested × (1 + i) + saving ÷ 12, with i the monthly real return
Worked example
Spending 40,000 a year means a FIRE number of 1,000,000 at a 4% withdrawal rate. With 50,000 invested and 25,000 saved a year at a 7% return and 2.5% inflation, you get there in 21.4 years, at 51.
Sources
- Bengen, “Determining Withdrawal Rates Using Historical Data”, Journal of Financial Planning, 1994 The origin of the 4% rule.
- Cooley, Hubbard and Walz, “Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable”, AAII Journal, 1998 The “Trinity study” of withdrawal rates over 15 to 30 years.
- Brealey, Myers and Allen, Principles of Corporate Finance, chapter 2 The standard formulas for loan payments, compounding and present value, the same as a spreadsheet’s PMT and FV.
Sources checked September 29, 2026. 6 automated tests check its answers on every change.
About the FIRE calculator
FIRE stands for financial independence, retire early. The idea is simple: once your investments can pay for your life, working becomes optional. This calculator finds that point from three numbers you control: what you spend, what you save and what you have already invested.
The target, your FIRE number, is your yearly spending divided by a safe withdrawal rate. At 4% it is 25 times your spending: spend 40,000 a year and you need a million. The 4% comes from research on 30-year retirements; retiring early means a longer retirement, so many people use 3–3.5% to be safer.
Spending is the strongest lever, because it works twice. Spending less lowers the target and leaves more to invest each year. That is why the share of your income you save matters more than the size of your income: someone saving half of what they earn can reach independence in about 16 years, whatever they earn.
Everything here is in today’s money, with the return after inflation. Returns vary from year to year, and a bad run early in retirement hurts most. Taxes on withdrawals, healthcare before state pension age and state pensions or Social Security later on all change the picture, so treat the result as a guide and keep a margin.
Questions people ask
What is a FIRE number?
The amount you need invested to live off it: your yearly spending divided by your withdrawal rate. At 4%, 25 times what you spend in a year.
How long does it take to reach FIRE?
It depends mostly on the share of your income you save. At a 5% real return, saving 25% takes about 32 years, 50% about 16 years and 70% about 9 years.
Is 4% a safe withdrawal rate for early retirement?
It was designed for about 30 years. For 40 years or more, many people plan with 3–3.5%, or stay flexible and spend less after bad years.
Should I count my home?
Only if you plan to sell it or rent it out. A home you live in doesn’t pay your bills, though owning it outright lowers your spending.