Your FIRE number · today's money
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needed at age , after inflation.
Reach FIRE by
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Projected corpus
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Monthly to stay on track
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Corpus lasts to
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Wealth trajectory
Milestones on your path
The FIRE spectrum
today's moneyLean
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Frugal: 70% of expenses.
Regular
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Your lifestyle at 4% rule.
Fat
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Generous: 150% of expenses.
Coast
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Invest once, coast to FIRE.
How the number is built
The math, in plain terms.
01. The 4% rule
Your FIRE number is your annual expenses divided by a safe withdrawal rate. At 4% that's 25× your yearly spend, a portfolio historically able to fund withdrawals indefinitely.
02. Real returns
We compound your contributions at your expected return, then measure the target against inflation, so a dollar at retirement is weighed in retirement's money, not today's.
03. Your real life
A step-up on contributions, one-time goals, an emergency buffer and a de-risked post-FIRE return all fold in, the messy parts a plain 25× rule quietly ignores.
Defaults use nominal US figures. A 7% pre-retirement return, 3% inflation and the classic 4% withdrawal rate. These are illustrative assumptions, not financial advice; markets vary and your mileage will too. Adjust every input to match your own plan.
The FIRE spectrum
What is a FIRE calculator?
Real Fire Calculator is a FIRE calculator: a tool for working out when you can reach Financial Independence, Retire Early, and how much you need saved to get there. Most calculators stop at the textbook shortcut of 25× your annual expenses. This one goes further, compounding your monthly contributions at your expected real return, discounting the result for inflation, and layering in the details a plain multiplier ignores: a savings step-up as your income grows, one-time goals like a wedding, a home or your kids' education, an emergency buffer, and a more conservative return once you've actually retired. Every field updates your numbers instantly, so you can see exactly how a raise, a slower market, or retiring five years earlier moves your target.
Which FIRE number is right for you?
FIRE isn't one number. It's a spectrum, and picking the wrong end of it can leave you either grinding years past when you were actually ready, or retiring into a budget you can't live with. This calculator breaks your target into five variants, side by side, using your own expenses and assumptions:
Lean FIRE calculator
A lean FIRE calculator targets the minimum: roughly 70% of your current spending, for a frugal, no-frills retirement. It's the fastest path to independence, but it leaves little room for lifestyle creep, travel, or an unplanned expense once you've stopped earning.
Coast FIRE calculator
A coast FIRE calculator asks a different question: have you already saved enough that, left completely untouched, compound growth alone will carry you to your number by retirement age, no further contributions required? The best coast FIRE calculators account for your actual real rate of return and time horizon rather than a flat growth assumption, this one included, so you know exactly how much runway you have to ease off.
Barista FIRE calculator
A barista FIRE calculator sits between coasting and full retirement: part-time or lower-stress work covers your day-to-day costs while your portfolio keeps compounding toward the rest. It's the plan for people who want to step back from a career, not disappear from the workforce entirely.
Chubby FIRE calculator
Chubby FIRE is the comfortable middle ground between lean and fat: more spending room than a bare-bones budget, without needing fat FIRE's full cushion. Run this chubby FIRE calculator at roughly 110–130% of your current expenses to see what that middle path actually costs.
Fat FIRE calculator
On the generous end, a fat FIRE calculator plans for around 150% of today's expenses, a retirement with real room for travel, hobbies, and a wider safety margin. It costs more to reach, but it costs less to live once you're there.
Traditional FIRE calculator
The original framework where you save 50% or more of your gross income. This targets a standard lifestyle by building a corpus of 25 times your annual expenses, allowing for a standard 4% safe withdrawal rate.
What makes this the best FIRE calculator for retirement planning?
Most FIRE calculators stop at 25× expenses and call it done. This one is built to be the best FIRE calculator for people who want their plan to survive contact with reality: real, inflation-adjusted returns instead of nominal ones; a contribution step-up that mirrors an actual career; one-time goals with their own timelines instead of one lump target; and a separate, more conservative return assumption once you're retired, because a portfolio you're withdrawing from shouldn't be modeled the same way as one you're still filling. Every input is editable and every output recalculates instantly, live in the browser. There's no signup, no email gate, and no cost: this FIRE calculator is, and will stay, completely free.
None of this replaces a financial advisor, and the defaults (a 7% pre-retirement return, 3% inflation, a 4% safe withdrawal rate) are illustrative starting points, not predictions. Adjust every assumption to match your own plan, and re-run the numbers whenever your income, expenses or goals change. See the methodology above for exactly how each number is calculated.
Frequently asked questions
FIRE calculator FAQ
What is the 4% rule for FIRE?
The 4% rule says you can withdraw 4% of your portfolio in your first year of retirement, then adjust that dollar amount for inflation every year after, without running out of money over a roughly 30-year retirement. It comes from historical U.S. market backtesting and is the shortcut behind the "25× expenses" FIRE number: divide your annual spending by 4% (or multiply by 25) to get your target portfolio.
What is a FIRE calculator?
A FIRE calculator is a tool that estimates how much you need saved, and how long it will take to get there, to reach Financial Independence, Retire Early. Real Fire Calculator takes your income, expenses, savings rate and return assumptions and projects a full wealth trajectory to your FIRE number, updating instantly as you adjust any input.
How long will $1,000,000 last using the 4% rule?
At a 4% withdrawal rate, $1,000,000 supports $40,000 of annual spending, adjusted for inflation each year, and is designed to last 30+ years without depleting the portfolio, assuming a diversified stock and bond mix and historical U.S. market returns. A run of poor returns early in retirement can shorten that; a lower withdrawal rate or flexible spending adds a safety margin.
Is 7% a safe withdrawal rate?
No. A 7% withdrawal rate is well above what the historical data supports; research on 30-year safe withdrawal rates, starting with the Trinity Study, puts the safer figure closer to 4%. Withdrawing 7% a year meaningfully raises the odds of running out of money, especially if a downturn hits early in retirement. 7% is more commonly cited as an expected long-run market return, not a withdrawal rate.
Why is SWR 4%?
The 4% figure comes from the Trinity Study (1998) and later research, which tested withdrawal rates against nearly a century of historical U.S. stock and bond returns, including the worst 30-year stretches like the Great Depression and 1970s stagflation. 4% was roughly the highest rate that survived nearly every historical 30-year period without the portfolio hitting zero, which is why it became the standard "safe" starting point.
How do I calculate FIRE?
Take your target annual spending in retirement and divide it by your safe withdrawal rate (4% → multiply by 25) to get your FIRE number. Then work out how long your current savings and monthly contributions, compounding at your expected real, after-inflation return, take to reach that number. This calculator does that math for you, and layers in real-life factors like a savings step-up, one-time goals and an emergency buffer that a plain 25× estimate skips.
How to retire by 40?
Retiring by 40 means maximizing the two levers you control: savings rate and time. In practice that means keeping expenses well below income, investing the difference consistently, increasing contributions with every raise, and starting as early as possible so compounding has decades to work. Run your own income, expenses and current savings through the calculator above to see whether your trajectory actually lands at 40, and what changes if it doesn't.
Is 100k saved by 40 good?
It depends entirely on your expenses, income and how many years you have until you want to retire; there's no single number that's "good" for everyone. $100k by 40 is a meaningful head start if your expenses are modest and you have 20+ years of runway for compounding, and less far along the path if you're aiming for early retirement with high spending. Plug your own figures into the calculator to see your actual trajectory rather than benchmarking against a generic milestone.
Can I retire early?
Yes, if your savings, expected returns and spending plan support it, which is exactly what this calculator is built to check. Early retirement is a function of your savings rate and time horizon more than your income alone: someone saving 50%+ of their income can often reach FIRE in 15–20 years. Enter your numbers above to see your specific FIRE age.
What is the best FIRE calculator?
The best FIRE calculator goes beyond the textbook 25× shortcut: it uses real, inflation-adjusted returns, lets you model a savings step-up as your income grows, accounts for one-time goals like a home or a wedding, and uses a more conservative return once you've actually retired. Real Fire Calculator does all of this, live in the browser, for free, with no signup required.
How to calculate FIRE amount?
Your FIRE amount is your annual expenses divided by your safe withdrawal rate, most commonly 4%, which is the same as multiplying annual expenses by 25. For example, $50,000 in annual expenses implies a $1,250,000 FIRE number at a 4% withdrawal rate. This calculator refines that baseline further by adjusting for inflation, your expected return, and any one-time goals you plan to fund from the same portfolio.