FIRE Calculator
Your FIRE number, your savings rate, and the exact month work becomes optional — no mysticism, just the math.
Finance tools · Free
About the FIRE Calculator
FIRE — Financial Independence, Retire Early — comes down to one number and one date. Your FIRE number is the portfolio that can fund your spending forever at a safe withdrawal rate. Your FI date is when your savings and investment growth get you there. This calculator gives you both, plus the savings rate that drives everything.
Enter your age, your invested net worth (investable assets only — not your home), your after-tax income, how much you invest each year, a real (after-inflation) return, your expected annual spending in retirement, and a withdrawal rate. The result is the month and year work becomes optional, and a chart of your path to the FIRE line.
The FIRE number is just spending divided by withdrawal rate. At the classic 4% rule, $60,000 a year of spending needs $1.5 million. Drop the withdrawal rate to 3.5% for more safety and the target rises; trim spending and it falls fast — every $1,000 of annual spending you cut removes $25,000 from the target at 4%.
Savings rate beats returns. Market returns are out of your control; the share of income you invest is not. Moving from a 15% to a 30% savings rate can pull the FI date forward by years — and by close to a decade if the extra savings come from lower spending, which also shrinks your FIRE number (lower the spending field to see it).
Use real returns. Because spending is held flat in today's dollars, enter an inflation-adjusted return — 5–7% is a commonly used range for a stock-heavy portfolio, not a guarantee. The model is deliberately simple: constant returns, no taxes or fees, flat spending. Reality will wobble; the direction is what matters. This is general education, not financial advice.
How to use it
- Enter your age and invested net worth. Count investable assets only — retirement accounts, brokerage, cash you'll invest.
- Enter income and annual savings. The calculator shows your savings rate live.
- Set a real return. After inflation — 5-7% is a reasonable range for stocks.
- Enter retirement spending and withdrawal rate. 4% is the classic rule of thumb; lower is more conservative.
- Read your FIRE number and FI date. See the target portfolio and the month work becomes optional.
- Follow the action plan. Automate the savings, watch your savings rate, and re-run yearly.
Frequently asked questions
How does the FIRE calculator work out years to financial independence?
It solves the future-value-of-annuity equation for the number of years until your invested net worth, plus annual savings growing at your real return, reaches your FIRE number. With the defaults (age 32, $75,000 invested, $35,000 saved a year, 7% real return, $60,000 spending, 4% withdrawal) the FIRE number is $1.5 million and you get there in about 18.4 years, around age 50.
Why does the FIRE calculator use a real return instead of a nominal return?
Your retirement spending is entered in today's dollars and held flat, so the portfolio growth must also be in today's dollars, after inflation. Entering a nominal return such as 10% would pull your FI date unrealistically early. Subtract your expected inflation from the return you expect to get a real figure.
How does the FIRE calculator's savings rate affect my FI date?
The savings rate shown is annual savings divided by after-tax income (31.8% with the defaults), and below 30% the action plan flags it as your biggest lever. The FI date itself uses your annual savings and retirement spending fields directly; spending isn't derived from income minus savings. If you plan to save more by spending less, lower the retirement spending figure too to see the full effect.
Is a 4% withdrawal rate safe for early retirement in the FIRE calculator?
The 4% rule comes from US historical studies of roughly 30-year retirements, and an early retirement can last 40 years or more, so many planners use 3–3.5% for extra margin. In the default scenario, dropping to 3.5% raises the FIRE number to about $1.71 million and pushes the timeline to about 19.9 years. This is general education, not financial advice; confirm with a qualified professional.
What does the FIRE calculator leave out?
It assumes constant returns and steady annual savings, and ignores taxes on withdrawals, investment fees, healthcare costs before Medicare, Social Security and the risk of a bad market early in retirement (sequence-of-returns risk). If the math puts FI more than 80 years away it asks you to adjust inputs, and if your invested net worth already covers the FIRE number it shows 'Already there'.
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