Put in your take-home pay, what you spend and what you have already invested. The calculator works out your FIRE number, how many years until you reach it and your Coast FIRE number, and it shows the math underneath so you can check every figure.
Save $46,800 a year (52% of take-home pay) and, at a 5% real return, you’d reach $1,080,000 in about 15.7 years: age 46, in 2042.
Estimates in today’s dollars, assuming the same return after inflation every year. Real markets don’t move in a straight line, so treat the year as a rough guide, not a guarantee. How it works
How this FIRE calculator works
Three numbers do all the work. Your FIRE number is your yearly spending divided by your withdrawal rate: $43,200 at 4% is $1,080,000, the familiar “25 times spending” rule. Your savings are take-home pay minus spending, invested every year. Your real return is what the portfolio earns after inflation, so every result stays in today’s dollars.
The calculator then finds the year your invested savings, compounding at that return, first reach your FIRE number. It assumes you invest once a year and keep spending flat in real terms, which is how most early-retirement plans are built.
What is a FIRE number?
It is the size of portfolio that could pay your spending for the rest of your life. The 4% figure comes from studies of 30-year retirements in US market history (Bengen in 1994, then the Trinity study in 1998), where a 4% first-year withdrawal, raised with inflation, lasted in most or all historical periods. Retiring at 40 can mean planning for 50 years, and research on longer retirements generally supports a lower starting rate; the 4% rule vs 3.5% walks through the evidence. Set the withdrawal rate to 3.5% above and your number rises to 28.6 times spending. No rate guarantees the money lasts.
Why your savings rate matters more than your return
Saving more shortens the road from both ends: you invest more every year, and you need less at the finish because you have learned to live on less. The table uses your take-home pay, savings and return from the calculator and shows how many years each savings rate takes.
| Savings rate | You save | You spend | FIRE number | Years to FI |
|---|---|---|---|---|
| 10% | $9,000 | $81,000 | $2,025,000 | 51.4 |
| 20% | $18,000 | $72,000 | $1,800,000 | 36.7 |
| 30% | $27,000 | $63,000 | $1,575,000 | 28.0 |
| 40% | $36,000 | $54,000 | $1,350,000 | 21.6 |
| 50% | $45,000 | $45,000 | $1,125,000 | 16.6 |
| 60% | $54,000 | $36,000 | $900,000 | 12.4 |
| 70% | $63,000 | $27,000 | $675,000 | 8.8 |
Returns still matter, which is why fees do. Left to grow for 30 years at a 5% real return, $500,000 ends about $270,000 lower with a 0.50% yearly fee than with 0.03% (the calculation). See what the big three charge in Fidelity vs Vanguard vs Schwab.
Coast FIRE, Lean FIRE and Fat FIRE
- Coast FIRE: you have enough invested that, without adding another dollar, it grows to your FIRE number by 65. The Coast FIRE figure above is that amount. Our Coast FIRE guide works through the formula with examples.
- Lean FIRE: an informal label for a FIRE number built on a modest budget. There’s no official dollar line.
- Fat FIRE: a number with room for travel, a bigger home and a buffer. Lean FIRE vs Fat FIRE builds both from example budgets.
What to do once you know your number
- Invest the yearly savings in low-cost index funds; the three-fund portfolio guide shows a simple setup, and our brokerage comparison sets out what each firm charges.
- Keep your emergency fund out of the market, in an insured account; here’s how to choose a high-yield savings account.
- In a taxable account, understand tax-loss harvesting and the wash-sale rule.
- Plan early access to retirement accounts with a Roth conversion ladder.
Assumptions and limits
This is a planning tool, not financial advice, and every result is an estimate. It assumes the same return every year and ignores taxes on withdrawals, Social Security, pensions and the order of returns, which matters most in the first years of retirement (sequence-of-returns risk). The 5% default return after inflation is an assumption, not a forecast; try 3% or 4% to see how much margin your plan has. Read how we make money.
FIRE calculator FAQ
How much do I need to retire early?
About 25 times your yearly spending at a 4% withdrawal rate, or about 28.6 times at 3.5%. Someone spending $40,000 a year needs between $1,000,000 and $1,140,000.
How long does it take to reach FIRE?
It depends mostly on your savings rate. Starting from zero at a 5% real return, saving 50% of take-home pay takes about 17 years; saving 25% takes about 32.
Does the calculator account for inflation?
Yes, by working in real terms. Enter a return after inflation and read every result in today’s dollars.
What is a good savings rate for FIRE?
At 50% you reach FI in about 17 years from scratch; at 70% it takes under 9. Use the savings rate table to see your own numbers.