Your FIRE number — Financial Independence, Retire Early — is the investment portfolio size that lets you live off returns indefinitely without ever working again. Calculated as annual expenses × 25 (the inverse of the 4% safe withdrawal rate), it is the cornerstone of the FIRE movement. This free calculator shows your Regular, Lean, Fat, and Coast FIRE targets alongside a year-by-year projection of your path to financial independence.
Your Financial Details
FIRE Numbers by Mode
Year-by-Year Projection
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How to Use the FIRE Number Calculator
Financial Independence, Retire Early (FIRE) is a movement built around a deceptively simple idea: save and invest enough that your portfolio generates more income than you spend. The magic number that makes this possible is called your FIRE number. This calculator helps you find yours in seconds and shows exactly how long your current trajectory will take to get there.
Step 1: Enter Your Annual Expenses
Start with your current annual spending — this is the single most important input. Your FIRE number is directly tied to your expenses, not your income. Enter your total yearly expenditure including rent or mortgage, food, transport, entertainment, and everything else. Even small reductions in spending dramatically shrink your FIRE number and accelerate your timeline.
Step 2: Enter Your Current Savings and Monthly Contributions
Enter the total value of your invested assets today — index funds, 401k, IRA, brokerage accounts, and any other investment accounts. Then enter how much you add each month. This monthly savings figure is what drives your progress. The calculator models growth with compound interest applied to both your existing savings and ongoing contributions.
Step 3: Set Your Return Rate and Ages
The expected annual return models investment growth before you retire. A historically reasonable figure for a diversified stock index portfolio is 7% in real (inflation-adjusted) terms. Enter your current age and your desired retirement age — these two numbers drive the Coast FIRE calculation and allow the year-by-year projection table to display your age alongside each year's portfolio value.
Step 4: Choose a Safe Withdrawal Rate
The safe withdrawal rate (SWR) determines how much you can spend per year in retirement without running out of money. The classic 4% rule comes from the Trinity Study and has historically succeeded over 30-year retirements. If you plan to retire very early — say at 40 with a 50+ year retirement — consider 3.5% or 3% for added safety. Selecting a lower SWR increases your FIRE number but reduces long-term risk.
Step 5: Understand the Four FIRE Modes
Regular FIRE targets your current expense level. Lean FIRE assumes you cut expenses by 30%, useful for modelling a frugal early retirement or living in a low-cost-of-living area. Fat FIRE adds 50% to your expenses, covering a more comfortable or travel-heavy retirement lifestyle. Coast FIRE is unique: it tells you how much you need invested right now so that — with zero future contributions — compound growth alone will carry you to your full FIRE number by your target retirement age. Reaching Coast FIRE is a major milestone because it means you can relax your savings rate and only cover living expenses.
Step 6: Read the Year-by-Year Projection
The projection table shows your portfolio value at the end of each year, alongside annual contributions and investment growth. Rows that reach or exceed your Regular FIRE number are highlighted so you can see your financial independence date at a glance. Use this table to model "what if" scenarios — try increasing monthly savings by $500 or adjusting your return rate to see how the timeline shifts. All calculations run privately in your browser; nothing is stored or transmitted.
For a detailed walkthrough, see our guide: Reaching Your FIRE Number on Average Salary.
FAQ
Is this FIRE Number Calculator free?
Yes, this FIRE number calculator is completely free with no signup, no account, and no hidden fees. All calculations run entirely in your browser using client-side JavaScript. You can experiment with unlimited scenarios without sharing any personal data.
Is my financial data safe and private?
Absolutely. Everything runs locally in your web browser — your income, expenses, and savings figures are never sent to any server. You can even disconnect from the internet after loading the page and the calculator will continue to work perfectly.
What is a FIRE number?
Your FIRE number is the total amount of invested assets you need to retire early and live off investment returns indefinitely. It is typically calculated as your annual expenses multiplied by 25, which corresponds to a 4% annual withdrawal rate — the amount research suggests you can withdraw each year without depleting your portfolio over a 30-year period.
What is the difference between Lean FIRE, Regular FIRE, and Fat FIRE?
Lean FIRE targets a minimal lifestyle with very low annual expenses (often under $40,000 for a household), requiring a smaller FIRE number. Regular FIRE covers a comfortable middle-ground budget. Fat FIRE aims for a generous lifestyle with higher annual spending, requiring a significantly larger portfolio. This calculator lets you enter custom expense amounts for each mode.
What is Coast FIRE and how is it different?
Coast FIRE is the amount you need invested right now so that — even if you make zero additional contributions — your portfolio will grow to your full FIRE number by your target retirement age. Once you reach Coast FIRE, you only need to cover your current living expenses from income, with no need to save further for retirement.
What safe withdrawal rate should I use?
The traditional FIRE safe withdrawal rate is 4%, based on the Trinity Study showing a 30-year retirement success rate above 95% for stock-heavy portfolios. If you are retiring very early (40+ year retirement), many FIRE practitioners prefer 3.5% or 3% for extra safety. This calculator shows your FIRE number under all three rates so you can see the difference.
How accurate are the year-by-year projections?
Projections use standard compound growth formulas with your entered annual return rate and monthly savings. They assume consistent contributions and a fixed return, which is a simplification — real market returns vary year to year. Use the projections as a planning guide, not a guarantee. A financial adviser can help account for taxes, inflation, and sequence-of-returns risk.
What annual return rate should I enter?
A commonly cited long-term average for a diversified index fund portfolio is 7% per year in real terms (adjusted for inflation). In nominal terms (before inflation), historical US stock market averages are closer to 10%. If you want to be conservative, use 5–6%. The calculator lets you set any rate so you can model best-case and worst-case scenarios.