Withdrawal rate caveat
The common 4% style shortcut is only a planning heuristic. Actual sustainable withdrawals depend on asset allocation, fees, taxes, sequence of returns, inflation and retirement length.
Example
If annual expenses are 40,000 and you use a 4% withdrawal rate, the target portfolio is 40,000 / 0.04 = 1,000,000. If you already have 150,000 invested, the remaining gap is 850,000 before future growth and contributions.
Common mistakes
Do not treat the FIRE number as a guaranteed retirement amount. Housing costs, healthcare, taxes, market downturns and one-time expenses can change the amount you need.
Limitations
This calculator does not run a full retirement simulation and does not provide investment advice. Use it as a first estimate, then test several spending, inflation and return scenarios.
Last reviewed: 2026-05-17