Financial Independence Number Calculator

Last updated July 2, 2026

The financial independence number — sometimes called the FIRE number — is the portfolio size at which passive income from investment returns can sustain indefinite living expenses without depleting the principal. The most common formula uses the 4 percent rule as its foundation: your FI number equals your annual expenses divided by 0.04, or equivalently, your annual expenses multiplied by 25. Annual expenses of $60,000 require a portfolio of $1,500,000 to be financially independent at the 4 percent withdrawal rate. Annual expenses of $40,000 require $1,000,000. Annual expenses of $80,000 require $2,000,000.

For early retirement scenarios — where the withdrawal period extends beyond 30 years — most researchers recommend a more conservative 3.3 to 3.5 percent withdrawal rate, corresponding to a multiplier of 28 to 30 times annual expenses. Social Security, pension income, or part-time work income reduces the portfolio requirement proportionally: a person expecting $20,000 per year in Social Security at retirement who needs $60,000 per year total only needs the portfolio to cover $40,000 — a FI number of $1,000,000 rather than $1,500,000. The savings rate needed to reach any given FI number — and the number of years it takes at various savings rates — follows a well-documented mathematical relationship: increasing savings rate from 15 to 25 percent of income typically cuts the time to financial independence by five to seven years.

The FI calculation shows annual essential expenses multiplied by 25, or 28 to 30 for early retirement, then compares the current portfolio with the target portfolio. Dividing that gap by annual investment contributions estimates years to FI at the current rate, while higher-savings scenarios show how the timeline changes.