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FIRE basics

What FIRE is, how to work out your number and how its versions compare, with every figure calculated.

What financial independence means, the five versions and how much each one costs.

Where the 4% rule comes from, how long a portfolio lasts at each rate and what the rule leaves out.

The formula, three worked examples, a table by spending level and how other income lowers it.

All five types for the same household: portfolio needed, age reached and what each one asks of you.

Calculators

Your FIRE number and the age you reach it for lean, regular and fat FIRE. $40,000 a year at a 4% withdrawal rate needs $1,000,000.

How much you need invested today to stop saving. $231,377 at 35 grows to $1,000,000 by 65 on its own.

Years your savings last at a fixed withdrawal, with a two-bad-years test. $40,000 a year from $1,000,000 lasts 44.1 years.

Your percentile among US families your age, from the Federal Reserve's 2025 survey. The median for all families is $216,100.

Last reviewed by Asier Fernández, editor, on October 18, 2026. Educational information only, not financial advice. How we calculate