FIRE Calculator
Find your FIRE number from annual spending and a safe withdrawal rate, then the years and age at which your savings and real returns get you there, charted.
FIRE Calculator: with the default inputs, fire number is $1,250,000.
Today's dollars. Include taxes and health insurance you'll pay yourself.
Amount invested each year, including employer match.
After inflation. Stocks have returned ~7% real long-run; 4–5% is a cautious plan.
4% is the classic rule for 30-year retirements; 3–3.5% is more conservative for 40+ years.
Portfolio needed: spending ÷ withdrawal rate.
- Years to FIRE
- 18.5
- Age at FIRE
- 48.5
- Progress toward FIRE
- 12%
- Savings rate
- 37.5%Savings ÷ (savings + spending) — assumes your current spending matches your retirement spending.
- Multiple of expenses needed
- 25
Assumptions
- All figures are in today's dollars; the return is real (after inflation) and constant.
- Savings are added at the end of each year and spending in retirement equals the amount entered, forever.
- No Social Security, pension, taxes on withdrawals or changes in spending are modelled.
| Year | Age | Portfolio |
|---|---|---|
| 0 | 30 | $150,000 |
| 1 | 31 | $187,500 |
| 2 | 32 | $226,875 |
| 3 | 33 | $268,219 |
| 4 | 34 | $311,630 |
| 5 | 35 | $357,211 |
| 6 | 36 | $405,072 |
| 7 | 37 | $455,325 |
| 8 | 38 | $508,092 |
| 9 | 39 | $563,496 |
How this is worked out
The formula
FIRE number = annual spending ÷ safe withdrawal rate (4% → 25× spending) Years to FIRE = ln[ (Target × r + S) ÷ (Portfolio × r + S) ] ÷ ln(1 + r) r = real (after-inflation) return, S = annual savings added at year end Everything is in today's dollars, so no separate inflation term is needed
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Annual spending in retirement
- Today's dollars. Include taxes and health insurance you'll pay yourself.in dollars · 0 or more · defaults to 50000
- Current invested portfolio
- A number.in dollars · 0 or more · defaults to 150000
- Annual savings
- Amount invested each year, including employer match.in dollars · 0 or more · defaults to 30000
- Expected real return
- After inflation. Stocks have returned ~7% real long-run; 4–5% is a cautious plan.a percentage · from -10 to 20 · defaults to 5
- Safe withdrawal rate
- 4% is the classic rule for 30-year retirements; 3–3.5% is more conservative for 40+ years.a percentage · from 0.5 to 20 · defaults to 4
- Current age
- A number.from 10 to 100 · whole numbers only · defaults to 30
What you get back
- FIRE numbermain answer
- Portfolio needed: spending ÷ withdrawal rate.
- Years to FIRE
- Age at FIRE
- Progress toward FIRE
- Savings rate
- Savings ÷ (savings + spending) — assumes your current spending matches your retirement spending.
- Multiple of expenses needed
What this assumes
- All figures are in today's dollars; the return is real (after inflation) and constant.
- Savings are added at the end of each year and spending in retirement equals the amount entered, forever.
- No Social Security, pension, taxes on withdrawals or changes in spending are modelled.
About this calculator
FIRE — financial independence, retire early — reduces to one number: the portfolio that can pay your living costs indefinitely. Divide annual spending by a safe withdrawal rate and you have it; at the classic 4% that's 25 times what you spend. Everything else is about how fast you get there, and that's set almost entirely by your savings rate.
How to use it
Enter what you'd spend per year once free (in today's money, including the taxes and health insurance an employer currently covers), what you've invested so far, how much you add each year, and a real return — after inflation — so the whole calculation stays in today's dollars. The default 5% real is a cautious figure for a stock-heavy portfolio; the 4% withdrawal rate is the well-known rule from the Trinity study and Bengen's 1994 paper.
Solve for is useful here: "what annual savings gets me there by 45?" or "what spending level could I sustain if I stopped at 50?"
Reading the results
- FIRE number is the target portfolio.
- Years to FIRE and age at FIRE come from compounding the current portfolio and adding savings each year until the target is hit.
- Savings rate is the figure the FIRE community obsesses over for good reason: it fixes the answer regardless of income. Saving 15% takes about 40 years from zero; 50% takes about 17; 70% about 8½ (at 5% real, 4% withdrawal).
- Progress is how far along you already are.
About the 4% rule
Bengen and the Trinity study found that withdrawing 4% of the starting portfolio, adjusted for inflation each year, survived every historical 30-year period in US data with a 50–75% stock allocation. Early retirees face longer horizons — 40, 50 or 60 years — where 3.25–3.5% is safer, and the rule assumes you never cut spending in a bad market, which real people do. Move the rate to see how much the target changes: going from 4% to 3.5% raises the FIRE number by 14%.
What the model leaves out
Social Security or a pension arriving later lowers the amount your portfolio must cover after that date; a paid-off house lowers spending; part-time income in early retirement is a huge lever ("Barista FIRE"). Taxes on withdrawals depend on which accounts the money sits in, and early access to 401(k)/IRA money needs a Roth conversion ladder or Rule 72(t) plan. Treat the age here as a base case, then stress it with a lower return and a lower withdrawal rate.
Frequently asked questions
▸What is a FIRE number?
The portfolio size that can fund your spending indefinitely: annual spending divided by a safe withdrawal rate. At 4%, spending $50,000 a year needs $1.25 million.
▸Is the 4% rule safe for early retirement?
It was derived for 30-year horizons. For 40–60 years, most analyses suggest 3.25–3.75% to keep failure risk low, and staying flexible about spending in bad markets matters more than the exact figure.
▸Why use a real return instead of a nominal one?
Because your spending target is in today's dollars. Using an after-inflation return keeps everything in the same units, so the FIRE number doesn't need to be inflated forward.
▸How much does my savings rate matter?
It's nearly everything. From zero, at a 5% real return and 4% withdrawal rate, a 25% savings rate takes about 30 years, 50% about 17, and 65% about 10. Income only matters through the rate.
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