FIRE number

How this FIRE number is built

A FIRE (financial independence) number is a planning identity, not a market guarantee:

FI number ≈ annual spend ÷ withdrawal rate

At a 4% withdrawal rate, $50,000 of annual spend implies a $1.25 million portfolio. At 3.5%, the same spend needs about $1.43 million. The rate is the lever: a lower rate means a larger pile for the same lifestyle.

Years to FI

The calculator also estimates how long it takes to reach that pile from current invested assets, annual savings, and a constant real (after-inflation) return. Treating the return as real keeps spend in today’s dollars. A 5% real return is a different claim than a 5% nominal return with 3% inflation.

Sequence-of-returns risk, fees, taxes, and a changing spend rate can move the date. Four percent is a common shortcut from historical US portfolio research. It is not an entitlement.

Worked sketch

Spend $50,000, withdrawal rate 4% → target $1,250,000.
Current invested assets $200,000, savings $25,000/year, 5% real return.

You are not 42 years away at $25k / year with no growth ($1,050,000 gap ÷ $25,000). Compounding on both the existing pile and new savings shortens that. Raise savings by $10,000/year and the date usually moves more than raising the assumed return by 0.5%. If years-to-FI looks absurd, the honest lever is spend or savings rate, not a 12% return box.

Pair with investment growth for a contribution schedule and net worth for a snapshot of what you already have.

Guide: FIRE number, savings rate, and years to FI.