FIRE Calculator
Calculate your Financial Independence / Retire Early (FIRE) number, how many years until you reach it, your savings rate, and Lean/Fat/Coast FIRE reference targets.
Input
Yearly spending you expect to need in retirement (today's dollars).
Annual portfolio return after inflation (historical stock market ~7%).
Output
| Metric | Value |
|---|---|
| No data yet | |
| Year | Starting Balance | Growth | Ending Balance |
|---|---|---|---|
| No data yet | |||
Guides
What is FIRE?
FIRE (Financial Independence, Retire Early) is a movement built around saving and investing aggressively so your portfolio can sustainably cover your living expenses well before traditional retirement age. The core idea rests on the "safe withdrawal rate" — the percentage of your portfolio you can withdraw each year, adjusted for inflation, without running out of money over a long retirement.
How this tool works
- Enter your current age, annual income (after tax), and annual expenses.
- Enter your current savings and expected real return (after inflation).
- Pick a safe withdrawal rate — 4% (the widely-cited Trinity Study result) is the default, with 3.5% for a more conservative target and 4.5% for a more aggressive one.
Your FIRE number is expenses × (100 / SWR) — the portfolio size whose safe withdrawals cover your expenses indefinitely. The tool simulates your savings growing year over year (existing balance plus annual savings, compounding at your expected return) to find how many years until you cross that number. The Year-by-Year Projection table shows the simulation in detail.
Lean, Fat, and Coast FIRE
Beyond the standard FIRE number, the summary includes three common variants:
- Lean FIRE (
expenses × 15) — a bare-bones target assuming a higher, less conservative withdrawal rate. - Fat FIRE (
expenses × 33) — a more comfortable target assuming a lower, more conservative withdrawal rate (roughly 3%). - Coast FIRE — the amount you'd need today to reach your FIRE number by traditional retirement age (65) purely through investment growth, with no further contributions.
Common uses
- Estimating how many years until financial independence based on your current savings rate
- Comparing how a higher savings rate or return assumption shortens your FIRE timeline
- Setting a Lean or Fat FIRE target instead of the standard 4%-rule number
- Checking whether you've already hit Coast FIRE — where growth alone gets you there
Privacy
This tool runs entirely in your browser. Your numbers are never uploaded to a server.
Use it from code
From 3 credits per callREST API
curl -X POST https://api.iotools.cloud/v1/tool/fire-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"currentAge": "30",
"annualIncome": "80000",
"annualExpenses": "40000",
"currentSavings": "20000",
"annualReturn": "7",
"swr": "4"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `fire-calculator` tool (FIRE Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.