Early Retirement (FIRE) Calculator
Project how many years until your portfolio reaches 25 times your annual expenses (the standard FIRE number).
Iterates year-by-year until the portfolio compounds past your FIRE number (25 times annual expenses).
How is this calculated?
FIRE number = 25 × annual expenses (4% safe withdrawal rate). Each year: corpus = corpus × (1 + return) + annual savings. Iterates until corpus ≥ FIRE number, capped at 80 years.
About this tool
The Early Retirement (FIRE) Calculator projects how many years separate you from the portfolio size at which the 4 percent safe-withdrawal rate covers annual spending. It iterates year by year until the corpus crosses 25 times annual expenses.
How it works
FIRE number = Annual expenses x 25 Annual savings = Annual income x Savings rate Each year: Corpus = Corpus x (1 + real return) + Annual savings Years to FIRE = first year where Corpus >= FIRE number
- Annual expenses = what you expect to spend each year in retirement, not your current gross salary.
- 25x multiplier = the inverse of the 4 percent rule. Use 28.6x for a 3.5 percent rule on longer retirements.
- Savings rate = (income minus spending) divided by income. Pre-tax 401(k) contributions count.
- Real return = inflation-adjusted annual return. Use 5 to 7 percent for a stock-heavy portfolio, not nominal 10 percent.
- Current savings = the head start. The closer to the FIRE number, the more compounding does the heavy lifting.
Worked example
Take the defaults: $50,000 savings, $80,000 income, 30 percent savings rate, 6 percent real return, $40,000 annual expenses.
- FIRE number: $40,000 x 25 = $1,000,000.
- Annual savings: $80,000 x 0.30 = $24,000 per year.
- Year 1 corpus: $50,000 x 1.06 + $24,000 = $77,000.
- Year 10 corpus: ~$405,000.
- Year 20 corpus: ~$1,043,000, crossing the $1M target.
Years to FIRE by savings rate
From a zero starting balance at 5 percent real return (Mr. Money Mustache, 2012). Real time-to-FIRE is shorter if you already have savings invested:
| Savings rate | Years to FIRE | Working years per retirement year |
|---|---|---|
| 10% | ~51 | ~5.1 |
| 20% | ~37 | ~3.7 |
| 30% | ~28 | ~2.8 |
| 40% | ~22 | ~2.2 |
| 50% | ~17 | ~1.7 |
| 65% | ~10.5 | ~1.05 |
| 75% | ~7 | ~0.7 |
| 85% | ~4 | ~0.4 |
Common mistakes
- Plugging in nominal returns. The 25x rule assumes a 4 percent real safe withdrawal. Use real (inflation-adjusted) returns of 5 to 7 percent, not 10 percent nominal.
- Using current gross income as retirement spend. The target is annual expenses in retirement, not your current paycheck. Mortgages get paid off, kids leave, and taxes drop.
- Excluding tax-deferred contributions from savings rate. Pre-tax 401(k) and pension contributions are still savings. Excluding them overstates years to FIRE.
- Ignoring sequence-of-returns risk. The last 5 years before FIRE are the most fragile. A pre-retirement drawdown can add 2 to 4 years.
- Forgetting healthcare. ACA subsidies cushion US early retirees, but plan for a 10 to 20 percent buffer on top of the textbook 25x.
- Treating FIRE as a hard stop. Most early retirees keep some part-time or passion income, which materially reduces required corpus.
Related calculators and glossary
Frequently asked questions
What is the FIRE number and why is it 25x expenses?
The FIRE number is the portfolio size that lets you stop working because investment returns plus safe withdrawals cover annual spending indefinitely. It is 25 times annual expenses because 25 is the inverse of the 4 percent safe withdrawal rate (1 / 0.04). If you spend $40,000 per year, you need $1 million. The 4 percent figure comes from the 1998 Trinity Study using historical US returns over 30-year retirements.
Does savings rate really matter more than income?
Yes. Mr. Money Mustache's 2012 table shows that time to FIRE depends almost entirely on the percentage of income saved, not the absolute amount. A 50 percent savings rate retires you in about 17 years from zero, 65 percent in 10.5 years, and 75 percent in 7 years, all assuming 5 percent real returns. A higher income lets you save more in absolute terms but only matters to the extent it lifts the rate.
What expected return should I use in a FIRE projection?
Use a real (inflation-adjusted) return, not a nominal one. For a stock-heavy portfolio (80 to 100 percent equities), 5 to 7 percent real is the planning range backed by long-run US data. A balanced 60/40 portfolio justifies 4 to 5 percent real. Plugging in 10 percent because that is what the S&P 500 averaged nominally over the last century will systematically understate your years to FIRE.
What if my current savings already cover part of the FIRE number?
The calculator handles this directly: the starting portfolio compounds at your expected real return while you add annual contributions on top. The closer you are, the more years-to-FIRE collapses, since compounding does more of the work than fresh contributions in late stages. This is the Coast FIRE idea.
How is Lean FIRE different from Fat FIRE?
Lean FIRE targets a minimalist retirement budget, typically under $40,000 per year for a household, so the corpus needed is around $1 million at 25x. Fat FIRE targets a more comfortable $100,000 to $200,000 spend, requiring $2.5 to $5 million. Barista FIRE and Coast FIRE sit in between, mixing part-time income or letting compounding finish the job.
Does the 4 percent rule still hold in 2026?
The original Trinity Study assumed a 30-year horizon. Early retirees with 40 to 60 year horizons should use 3.25 to 3.5 percent for a higher safety margin (32x to 31x), as Wade Pfau and Michael Kitces have shown. Higher 2026 starting valuations and lower expected bond returns also argue for a touch more conservatism than the textbook 4 percent.
Sources and further reading
- Cooley, Hubbard and Walz (1998) Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable, Trinity University - the "Trinity Study" behind the 4 percent rule and the 25x multiplier.
- Bengen, William P. (1994) Determining Withdrawal Rates Using Historical Data, Journal of Financial Planning - the original safe-withdrawal-rate paper.
- Mr. Money Mustache (2012) The Shockingly Simple Math Behind Early Retirement - the savings-rate-to-years table used above.
- Vanguard Research (2023) How America Saves and Principles for Investing Success - long-run real return assumptions for stock-heavy and balanced portfolios.