FIRE Number Calculator
Calculate your FIRE number (annual expenses ÷ safe withdrawal rate). Shows years-to-FIRE under three savings scenarios.
FIRE Number Calculator
FIRE number at different withdrawal rates
Years to FIRE under different saving scenarios
How to use the FIRE Number Calculator
Estimate your annual retirement expenses
Not today's expenses — what you'd spend per year in retirement, including healthcare, travel, kids out of the house, mortgage paid off. Most FIRE practitioners track 12 months of actual spending then adjust for known lifestyle changes.
Pick a Safe Withdrawal Rate
The 4% starting rate comes from William Bengen's 1994 paper and was corroborated by the Trinity Study (Cooley, Hubbard & Walz, 1998). In Trinity's data, 4% inflation-adjusted withdrawals over 30 years succeeded in 95-98% of historical periods for stock-heavy portfolios (50-100% stocks). 3.5% is the "conservative FIRE" rate for 40-50 year retirements. 3% for ultra-conservative.
Enter current portfolio + annual contribution
Current portfolio = invested assets only (not cash for spending, not home equity). Annual contribution = what you put into investments per year. The tool projects how many years it'll take to reach your FIRE number compounding at your real return.
Read the scenarios table
The tool computes years-to-FIRE under three saving scenarios — current pace, 50% more, and 2× current. The compounding effect on time-to-FIRE is non-linear; doubling your saving rate doesn't halve your time, but it gets dramatically close for early years.
FIRE — the math behind early retirement
FIRE — Financial Independence, Retire Early — is built on one elegant insight: if your investment portfolio can generate enough passive income to cover your annual expenses, you don't need to work for money any more. The "FIRE number" is the portfolio size that makes that math work. The shortcut formula is brutally simple: FIRE Number = Annual Expenses ÷ Safe Withdrawal Rate. At a 4% SWR, you need 25× your annual expenses. At 3.5%, you need ~28×. At 3%, you need ~33×. The relationship is hyperbolic — every percentage point you trim from your SWR shifts your target dramatically.
Where the 4% rule came from
The 4% rule traces to William Bengen's 1994 paper, which back-tested US stock-bond portfolios from every retirement start year since 1926 and found that 4% inflation-adjusted withdrawals never exhausted a 50/50 portfolio in under 33 years. The Trinity Study (Cooley, Hubbard & Walz, 1998) corroborated it with success rates: at 4% over 30 years, stock-heavy portfolios succeeded in 95-98% of historical periods. Bengen himself later published higher figures — 4.5% in 2020, and 4.7% in late 2025 on a broader multi-asset portfolio. Big ERN's "Safe Withdrawal Series" argues 3.25-3.5% for early retirees facing 40-50 year horizons. The honest answer: 4% is the Schelling point — well-supported, not bullet-proof, requires flexibility in down years.
25× annual expenses is the canonical FIRE target. 33× is conservative FIRE for 50-year retirements. Both are based on historical data — neither is a guarantee.
The APAC FIRE community
FIRE has active communities across the region — Singapore's 1M65 movement and the Seedly forums are the best-known examples. But the variables differ from the US case the research was built on: (a) healthcare in many APAC countries means either private insurance or staying near major-city public hospitals, which shapes the expense estimate; (b) the long-run return record is mostly a US record — the deep multi-decade datasets put US equities around 6.6% real (UBS Global Investment Returns Yearbook 2026, 1900-2025), and comparable series for ASEAN markets are thinner, so a US-calibrated 7% real assumption may not travel; (c) stronger family financial obligations (supporting parents, education for siblings) extend the cash-needs window. The tool's real-return input is exposed precisely so you can test a more conservative number (5-6% real) against the default.
Limitations to be honest about
The 4% rule is a probabilistic guide, not a guarantee. Three failure modes: sequence-of-returns risk (a market crash in early retirement is catastrophic — even with the same average return, a 50% drop in year 1 can wreck the math); healthcare inflation (US healthcare costs have risen 2-3× general inflation for decades; budget for that); longevity risk (the original 30-year horizon doesn't fit a 40-year-old retiree planning to live to 90). Standard mitigations: build flexibility into withdrawal rate (cut to 3% in down market years), keep a 1-3 year cash buffer to avoid selling in crashes, plan for 35-50 years rather than 30.
10 Things to Know About FIRE
The 4% rule started with William Bengen's 1994 paper; the Trinity Study (1998) corroborated it. Trinity's authors — Cooley, Hubbard, Walz — were business professors at Trinity University in Texas.
The FIRE multiplier: at 4% SWR, you need 25× annual expenses. At 3.5%, 28.6×. At 3%, 33.3×. Each percentage point matters enormously.
A 50% savings rate ≈ 16 years to FIRE from zero — Mr. Money Mustache's famous 2012 table, which assumed 5% returns after inflation. At 7% real the same math gives ~15 years. Most FIRE math is variations on this fixed point.
FIRE has subtypes: Lean FIRE (lower spend, faster), Fat FIRE (higher spend, more time), Coast FIRE (one big front-loaded contribution, then coast), Barista FIRE (partial retire, part-time work for benefits).
The safe withdrawal rate isn't a withdrawal rate — it's a starting rate, then adjusted for inflation each year. Pulling out 4% literally each year (not inflation-adjusted) is different and more aggressive.
The 4% rule's research is stock-heavy: Bengen recommended holding 50-75% stocks; Trinity tested five mixes from 100% stocks to 100% bonds. At 4% inflation-adjusted over 30 years, Trinity's 25/75 bond-heavy mix succeeded only 71% of the time.
The biggest threat to FIRE is sequence-of-returns risk — a market crash in years 1-5 of retirement can wreck the math. A common mitigation: hold 1-3 years of cash to avoid selling stocks in down years.
Bengen kept revising his own rule: 4.5% in 2020 (his "SAFEMAX", worst case retiring October 1968), then 4.7% in late 2025 on a broader multi-asset portfolio. The 4% version is the floor his data supported, not his final word.
The FIRE philosophy traces to "Your Money or Your Life" (Vicki Robin & Joe Dominguez, 1992) — but the book never uses the acronym. "FIRE" itself spread online later, with no verified coiner; the 2010s blogs made it a movement.
Real return assumption matters more than nominal. The deep long-run datasets put US equities near 6.6% real (UBS Global Investment Returns Yearbook 2026, 1900-2025). Non-US-heavy portfolios deserve a more conservative test — run 5-6% and compare.
Frequently Asked Questions
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It's the Schelling point — well-supported by US historical data, not bullet-proof. Bengen himself later published higher figures (4.5% in 2020, 4.7% in late 2025 on a broader portfolio). Big ERN argues 3.25-3.5% for 40-50 year retirements. The honest answer: 4% is fine as a starting point, but build flexibility into your withdrawal strategy to handle down years.
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Everything you'll spend in retirement: housing, food, transport, healthcare, travel, hobbies, taxes, insurance. Exclude work-related costs (commute, work clothes, lunches) but add retirement-specific costs (more healthcare, more travel). Most FIRE practitioners track actual spending for 12 months then adjust 10-15% up for buffer.
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The deep long-run datasets put US equities around 6.6% real, inflation-adjusted (UBS Global Investment Returns Yearbook 2026, 1900-2025). A balanced stock-bond portfolio lands lower. Comparable multi-decade series for ASEAN markets are thin, so treat any regional figure with suspicion. Use 6-7% if mostly in US/global stocks; 5% for a balanced portfolio; 4% for conservative.
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No — your home generates housing services, not investment income. The exception: if you plan to downsize and unlock equity in retirement, count the planned net proceeds as portfolio. For most users, exclude home equity entirely and budget retirement housing costs separately in annual expenses.
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Treat them as expense reducers. If Social Security / CPF Life / your DB pension pays $X/year starting at age 65, subtract $X from your annual expenses for years 65+. Most FIRE practitioners do the math two ways: portfolio-only (conservative) and portfolio-plus-state-benefits (realistic).
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Coast FIRE = the portfolio size where compounding alone (zero further contributions) gets you to full FIRE by traditional retirement age. It's the "one-and-done" milestone — you stop saving aggressively and let time do the work. See our Coast FIRE Calculator for the specific math.
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The math works anywhere — but the variables differ. ASEAN salaries are lower in USD terms, expenses are lower, healthcare costs are different, equity returns historically lower. Use a more conservative real return (5-6% instead of 7%) and plan for longer retirements (50+ years if FIRE'ing at 40 in Singapore is reasonable given life expectancy).
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Build it into your annual expenses estimate. If you currently spend $40K but plan to travel more in retirement, model $55-60K. The SWR already adjusts for general inflation — what you need to add is the lifestyle adjustment specific to retired life (more leisure, more travel, more healthcare).
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Three levers, in order of impact: (1) increase savings rate — the highest-leverage move; doubling savings rate roughly halves time to FIRE; (2) cut expenses — lowers both your savings target AND your annual outflow, double effect; (3) increase return — modest improvements compound dramatically over long horizons, but don't reach for risk to do it.
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No. All calculation happens entirely in your browser via JavaScript. Open DevTools → Network and watch — there's zero outbound traffic. Safe for confidential personal finance modelling.
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