FIRE Number Calculator

Last updated July 2, 2026

The FIRE number — from the Financial Independence, Retire Early movement — is the portfolio size at which passive investment returns can sustain living expenses indefinitely without depleting the principal. The calculation follows directly from the 4 percent rule: multiply annual expenses by 25 to get the FIRE number. Annual expenses of $50,000 require a $1.25 million portfolio. Annual expenses of $80,000 require a $2 million portfolio. For early retirement scenarios spanning 40 or more years, most FIRE researchers recommend a more conservative 3.3 to 3.5 percent withdrawal rate, producing a 28 to 30 times annual expense multiplier — pushing the target for $50,000 in expenses to $1.4 to $1.5 million.

Social Security, pension income, or anticipated part-time work income reduces the portfolio requirement proportionally. A household planning to claim $18,000 per year in Social Security at retirement who needs $60,000 annually only needs the portfolio to cover $42,000 — a FIRE number of $1.05 million rather than $1.5 million. The savings rate is the most powerful lever for shortening the timeline to FIRE: at a 50 percent savings rate (spending half of after-tax income and investing the rest), most middle-income households can reach financial independence within 15 to 17 years. At a 10 percent savings rate, the timeline extends to 40 or more years. The relationship between savings rate and years to FIRE is non-linear — each 10-point increase in savings rate produces progressively larger reductions in the time required.

The calculation shows your FIRE number as annual essential expenses times 25 (or times 28 to 30 for early retirement). Then calculate your current gap and divide by annual savings and investment contributions to estimate years to FI at your current rate. Model the timeline impact of increasing your savings rate by 5 to 10 percent — the compressing effect on years to FIRE is one of the more motivating outputs any financial calculator produces.