FIRE Calculator
Find your FIRE number and see exactly how many years stand between you and financial independence. Enter your income, expenses, and current savings — results update instantly, nothing leaves your browser.
Your Finances
Current Position
Assumptions
Your FIRE Number
$1,125,000
Enough to cover $3,750/month forever at a 4% withdrawal rate
Savings Rate
40.0%
Years to FI
17.7
Age at FI
48
Monthly Passive Income
$3,750
Coast FI Number: $327,820
Save $302,820 more to reach Coast FI — then contributions become optional.
For informational purposes only — not financial or investment advice. This calculator provides arithmetic estimates based on the inputs you provide. It does not constitute financial, tax, or investment advice, and should not be relied upon as the sole basis for any financial decision.
Key limitations to be aware of:
- Constant return assumption. Real investment returns fluctuate significantly year to year. Sequence-of-returns risk — poor returns in the early years of retirement — can deplete a portfolio far sooner than this model suggests, even if the long-run average return matches your input.
- The 4% rule has limits. The Trinity Study (on which the 4% rule is based) modelled a 30-year retirement. For a 40–60 year early retirement, several studies suggest a 3–3.5% withdrawal rate is more appropriate to maintain high historical success rates.
- No inflation modelling. Results are in nominal dollars. Over a 30–50 year horizon, inflation can halve real purchasing power. Consider reducing your assumed return rate by expected inflation (e.g. use 5% instead of 7% for a roughly inflation-adjusted projection).
- Taxes and fees not included. Capital gains tax, income tax on withdrawals, and fund expense ratios are not modelled. These can materially reduce real outcomes.
- Life events not modelled. Healthcare costs, family changes, unexpected expenses, and career interruptions are common in long early retirements and are not reflected in these projections.
Consult a qualified, independent financial adviser before making significant investment or retirement decisions.
How It Works
Enter income & expenses
Your annual income and expenses determine your savings rate and FIRE number. Lower expenses shrink both targets simultaneously — a double-win for FI.
Add your current position
Enter your age and combined value of all invested assets — index funds, 401(k), IRA, brokerage accounts. This is your compounding starting point.
Set your assumptions
Choose an expected annual return (7% is the FIRE community standard for diversified index funds) and a safe withdrawal rate (4% is most common; go lower for ultra-early retirement).
See your FI timeline
Your FIRE number, years to FI, Coast FI threshold, and monthly passive income all update live. Toggle the year-by-year schedule to track each milestone.
How to Use the FIRE Calculator
- Enter your annual income after tax — this is your take-home pay across all sources.
- Enter your annual living expenses — the total you spend per year on housing, food, transport, healthcare, and everything else.
- Enter your current age and the total value of your current savings and investments across all accounts.
- Set your expected annual return rate — 7% is a common long-term average for broadly diversified index funds (before inflation).
- Set your safe withdrawal rate — 4% is the FIRE standard; use 3–3.5% for a 40+ year retirement or 4.5–5% for a shorter one.
- Review your FIRE number, savings rate, years to FI, age at FI, Coast FI number, and monthly passive income — all update instantly.
- Toggle Show year-by-year accumulation schedule to see how your balance grows each year and what percentage of your FIRE number you reach.
Understanding the Results
| Result | What it means |
|---|---|
| FIRE Number | The portfolio size at which your investments, growing and generating returns, can sustainably cover your annual expenses without depleting principal. Calculated as Annual Expenses ÷ Safe Withdrawal Rate. |
| Savings Rate | The percentage of your after-tax income you save and invest each year. This is the single most powerful variable in your FI timeline — a higher savings rate means both faster accumulation and a smaller FIRE number. |
| Years to FI | How long it will take for your portfolio to reach your FIRE number at your current savings rate and assumed investment return. Modelled month by month for accuracy. |
| Age at FI | The age you will be when your portfolio crosses your FIRE number. |
| Coast FI Number | The minimum amount you need saved today so that — even if you never invest another dollar — your portfolio will compound to your full FIRE number by your target FI age. Once reached, you only need to earn enough to cover current expenses. |
| Monthly Passive Income | Your FIRE Number multiplied by your safe withdrawal rate, divided by 12. This is the estimated monthly income your portfolio will sustainably generate once you reach FI. |
What Is FIRE?
FIRE — Financial Independence, Retire Early — is a personal finance movement built around aggressively saving and investing a large portion of your income so that investment returns alone can cover your living expenses, removing the need to work for money. The core insight, popularised by the book Your Money or Your Life and quantified by the Trinity Study, is that a diversified investment portfolio of 25× your annual expenses (the inverse of the 4% withdrawal rate) is sufficient to sustain indefinite withdrawals across virtually all historical market conditions.
FIRE is not one-size-fits-all. Common variants include:
- Lean FIRE — reaching FI on a frugal budget, often under $40,000/year.
- Fat FIRE — FI with a generous lifestyle, typically $100,000+/year.
- Barista FIRE — reaching a partial FI number and supplementing with part-time work.
- Coast FI — saving enough to coast to full FI by a normal retirement age, then working just to cover current expenses.
Key Features
- FIRE number calculation from annual expenses and your chosen withdrawal rate
- Month-by-month accumulation modelling — no simplified formula shortcuts
- Savings rate display as a percentage of after-tax income
- Coast FI number with gap-to-Coast metric
- Monthly passive income at your target withdrawal rate
- Year-by-year schedule with FI progress percentage per year
- Works for Lean FIRE, Fat FIRE, Barista FIRE, and Coast FI scenarios
- 100% private — no account, no upload, no server
Frequently Asked Questions
What is a FIRE number?
Your FIRE number is the portfolio size that, invested and left to grow, can cover your annual expenses indefinitely. It is calculated as: FIRE Number = Annual Expenses ÷ Safe Withdrawal Rate. For example, spending $45,000/year at a 4% SWR gives a FIRE number of $1,125,000.
What safe withdrawal rate should I use?
The 4% rule (from the Trinity Study) is the FIRE community standard. For a 30-year retirement it has historically succeeded in nearly all market conditions. For a 40–50 year early retirement, many FIRE practitioners use 3–3.5%. For a shorter or more conventional retirement, 4.5–5% may be reasonable. The SWR you choose directly determines your FIRE number — a 3% SWR means a larger target than 4%.
What is Coast FI and why does it matter?
Coast FI is the savings milestone at which you can stop contributing to investments entirely and still reach your full FIRE number by your target FI age through compounding alone. It matters because once you're coasting, the income pressure changes dramatically — you only need to cover today's expenses, not save for the future.
Does this account for inflation?
The calculator uses nominal return rates. To approximate real (inflation-adjusted) results, reduce your return rate by your expected inflation rate — for example, use 5% instead of 7% if you expect 2% annual inflation. All dollar amounts are in today's purchasing power at your entered return rate.
Does this include taxes or investment fees?
No. The calculator does not model capital gains tax, income tax on withdrawals, fund expense ratios, or advisory fees. These can meaningfully affect real outcomes. For a more accurate picture, reduce your assumed return rate to account for fees (e.g., subtract 0.1–0.5% for low-cost index funds).
Is my financial data stored or shared?
No. All calculations run entirely in your browser using JavaScript. Nothing you enter is sent to or stored on any server.
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