Lean FIRE Calculator: the fast lane.
Lean FIRE is the fastest path to freedom — but it means a minimalist lifestyle: bare-bones budget for housing, food, insurance, and little else. Find the number, then decide if the trade is worth it.
Lean FIRE is financial independence on a minimalist budget — roughly $25,000 to $30,000 of annual spending in the US. The math is the same as any FIRE number (annual expenses ÷ safe withdrawal rate), but the inputs are smaller, so the target portfolio lands around $625,000 at a 4% SWR. The reward is speed: a smaller number is reachable years — sometimes a decade — earlier than a standard or Fat FIRE target. The cost is margin: a Lean portfolio has thin buffer for healthcare spikes, sequence-of-returns risk, or lifestyle creep. Lean FIRE favors geographic arbitrage, DIY skills, and a paid-off home. Many in the FIRE community use it as a barrier-free milestone, then keep growing toward a more comfortable standard.
Read the full explainer →Three steps to your number
- 1Start with Lean pre-selectedThe lifestyle segmented control loads with Lean ($25k/yr). Drag annual expenses to your real minimal number — some go as low as $15k, others stretch to $35k.
- 2Pick your withdrawal rate4% is the Trinity Study default. Because a Lean portfolio has less buffer, many planners dial down to 3.5% for extra safety.
- 3Read your number and your paceThe big number is your shore line. The Plan slider shows how a small monthly contribution hits it sooner than any other FIRE path.
Your numbers
bare-bones budget: housing, food, insurance, little else
That's 25.0× your annual spending — the classic 4% rule. At your current savings growing at 7%, you'd hit it around age 84 if you add nothing more.
Savings trajectory: age 35 → 55
Your savings grow at the real return rate (~3.9%). The dashed line is your FIRE number — the point where compounding alone gets you there.
| SWR | Multiplier | Target portfolio |
|---|---|---|
| 3% | 33.3× | $833,333 |
| 3.5% | 28.6× | $714,286 |
| 4% | 25.0× | $625,000 |
| 4.5% | 22.2× | $555,556 |
| 5% | 20.0× | $500,000 |
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The math, explained.
What is Lean FIRE? +
Is $25k a year actually livable? +
What’s the trade-off vs standard FIRE? +
Does Lean FIRE cover healthcare? +
How much faster is Lean FIRE than standard? +
Is this financial advice? +
How this number is calculated
Lean FIRE number = Minimal annual spending ÷ Safe withdrawal rate. With $25,000 and a 4% SWR, that’s $25,000 ÷ 0.04 = $625,000. It’s the same formula as the standard FIRE number — just with a smaller spending input.
This page is a preset route of the FIRE Number calculator engine (PRD §5.0): the lifestyle segmented control loads with Lean pre-selected at $25k/yr, and the same The Plan slider, Milestone Ladder, and SWR comparison table render underneath. Read why we use 7% average returns or the 25× rule breakdown.