Find your Lean FIRE number and the exact year you can retire on a minimalist budget.
A free Lean FIRE planner that turns your lean annual spending into a portfolio target, then projects the year you cross the finish line — using real returns and the Trinity-study 4% rule.
Direct answers to the most common questions, in plain language. Skim if you're in a hurry; dig deeper below.
Early retirement on a bare-bones budget of roughly $25K–$40K a year.
Lean FIRE means reaching financial independence on a minimalist budget — typically $25,000 to $40,000 of annual spending. Your portfolio needs to be about 25 times that number, which makes Lean FIRE achievable far earlier than traditional retirement.
About 25× your annual lean spending at a 4% withdrawal rate.
Take your bare-bones annual expenses and multiply by 25. For $30,000 a year, your Lean FIRE number is $750,000. The math comes from the 4% rule: 1 / 0.04 = 25, the multiple of spending a portfolio can safely cover.
It is a reasonable starting estimate, with caveats.
The 4% rule comes from the Trinity study, which tested 30-year retirements on historical US data. It is a good first estimate, but a 40+ year Lean FIRE retirement may want a slightly lower withdrawal rate (3.25–3.5%) to handle sequence-of-returns risk and unpredictable healthcare costs.
They differ by annual spending — roughly $30K vs $60K vs $120K.
Lean FIRE targets minimalist spending (around $30K/yr). Regular FIRE assumes a comfortable middle-class budget (around $60K/yr). Fat FIRE funds an upscale lifestyle (around $120K/yr). Each uses the same 25× multiple, so the FIRE number scales linearly with your spending.
The mechanics in short answers — no jargon, no upsell.
A 4% safe withdrawal rate implies your portfolio must be 25 times what you spend each year. So $30K of lean spending requires roughly $750K invested.
We simulate your current portfolio growing at the expected real return, plus your monthly savings added each month. Real return strips out inflation so the target stays in today's dollars.
The moment your portfolio balance reaches the Lean FIRE number, you are technically free. The calculator finds this month and converts it to years and your retirement age.
Returns are uncertain. The chart and comparison table show how lean spending vs. fatter spending shifts the date by years — that's the most important takeaway, not a precise dollar amount.
Designed so anyone can model their situation in under a minute, with or without a finance background.
A lean budget compresses the timeline dramatically — many Lean FIRE plans hit independence in 10–15 working years.
No vague "save more" — you get one portfolio target that, once hit, replaces your salary indefinitely.
Adjust spending and savings rate live and see exactly which lever moves your FIRE date most.
A chart of your portfolio crossing the Lean FIRE line makes long-term math intuitive.
Inputs use real (inflation-adjusted) returns, so your target spending in today's dollars stays meaningful.
See side-by-side how much later Regular FIRE and Fat FIRE arrive — and decide if the extra years are worth it.
Everything you might ask before, during, or after using this tool.
Multiply your lean annual expenses by 25. For $30,000 per year, you need roughly $750,000 invested. For $40,000, you need about $1,000,000. This assumes a 4% safe withdrawal rate; if you want a more conservative buffer for a long retirement, use 30–33× instead of 25×.
It is realistic but tight. $30K–$40K a year does not stretch far in high-cost cities, so most Lean FIRE plans involve geographic arbitrage — moving to lower cost-of-living areas, often outside major metros or abroad. Healthcare in the US is the single biggest line-item risk.
Use a real (inflation-adjusted) return. A diversified global stock portfolio has historically produced 6–7% real over long periods; mixed stock-bond portfolios closer to 4–5%. Using real returns means your spending target stays in today's dollars and you do not need to model inflation separately.
It is a reasonable starting point, not gospel. The Trinity study tested 30-year retirements. For a 40–50 year Lean FIRE retirement, many planners use a slightly lower withdrawal rate (3.25–3.5%) for safety, or stay flexible — cutting spending in down markets to manage sequence-of-returns risk.
In the US, healthcare is the single biggest threat to a Lean FIRE budget. ACA subsidies help significantly at lean income levels, but premiums, deductibles, and out-of-pocket maximums can still consume $8K–$15K a year per household. Build a realistic healthcare line into your lean spending number before trusting it.
Lean FIRE means you stop working entirely on a lean budget. Coast FIRE means you have invested enough early that compounding alone gets you to retirement — you only need to cover current expenses, not save further. Coast can be a great intermediate stop on the way to Lean or Regular FIRE.
For Lean FIRE plans starting in your 30s or 40s, treat Social Security as a small bonus rather than a foundation. It can meaningfully extend safety after age 62/67, but you should not rely on it to fund the early decades of retirement.
Geographic arbitrage is choosing where to live based on cost of living. Moving from a high-cost US city to a lower-cost region — or abroad to places like Portugal, Mexico, or parts of Southeast Asia — can shrink your lean number by 30–50%. For many Lean FIRE plans, geo arbitrage is the difference between feasible and not.
Other Lazysmirk tools that pair well with this one.
Project your Financial Independence number and the year you can retire — based on your savings, spending, and returns.
Find your Coast FIRE number — the portfolio value today that will compound to full financial independence by retirement with zero further contributions.
See your Barista FIRE number — the portfolio level where part-time work covers the gap and you can leave full-time work years earlier.
Plan a high-spending early retirement with $100k+ annual budgets. Calculates your fat FIRE number, gap to target, and the savings rate required to get there.
See your FI number, years to FI, and the date your portfolio crosses 25× expenses — based on your real savings rate.
Size your emergency fund to your real expenses and risk profile, then see exactly how many months until you hit the target.
Lean FIRE is the minimalist branch of the FIRE movement (Financial Independence, Retire Early). It targets early retirement on a deliberately small annual budget — typically $25,000 to $40,000 per year. The trade-off is simple: live on less, retire much sooner.
The number falls out of the 4% rule. If you can safely withdraw 4% of your portfolio each year, you need 25 times your annual spending invested. $30K of lean spending → $750K. $40K → $1M. That is the entire Lean FIRE thesis in two sentences.
The three flavors of FIRE differ only in lifestyle, not in math. Lean FIRE assumes you can be content on ~$30K a year. Regular FIRE plans for a comfortable middle-class lifestyle around $60K. Fat FIRE funds an upscale life — international travel, nicer housing, generous giving — typically $100K–$150K a year.
Because the 25× multiple is linear, the FIRE numbers scale: roughly $750K, $1.5M, and $3M+. But the time to reach them is not linear in your effort — Lean often arrives a decade earlier than Regular at the same savings rate.
The single biggest lever in Lean FIRE is not investment returns or savings rate — it is where you live. Spending $30K a year is grim in San Francisco and luxurious in Lisbon, Mexico City, or Chiang Mai. Many successful Lean FIRE plans involve moving, at least seasonally.
Even within the US, the difference between high-cost coastal metros and lower-cost mid-sized cities can be 40–50% on housing alone. Run your Lean FIRE number in the calculator above, then run it again with a 30% lower spending figure and see how many years you just gained.
In the US, healthcare is the single biggest threat to a lean budget. ACA subsidies are generous at low MAGI levels and can keep premiums small, but out-of-pocket maximums still range $7K–$18K per person per year. One bad medical event can blow a year of lean spending.
A realistic Lean FIRE plan budgets $6K–$12K per year per adult for healthcare, builds an HSA, and considers options like geographic arbitrage to countries with lower medical costs and universal coverage.
Two short notes worth reading before you trust any number on this page.
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