FIRE Number Calculator

FIRE (Financial Independence, Retire Early) is the invested amount whose return fully covers your living expenses, letting you stop depending on a salary.

Divide annual expenses by the safe withdrawal rate. With the 4% rule: annual expenses × 25. For example, £36,000 a year ÷ 4% = £900,000.

It is the idea that you can withdraw 4% of a diversified portfolio each year without depleting it long term. It corresponds to a portfolio of 25× annual expenses.

Your FIRE number — the amount whose investment return covers your expenses. It depends directly on the level of your annual spending.

The classic rule is 4%, but many prefer 3–3.5% for more safety, especially for early retirement and long time horizons.

The 4% rule assumes withdrawals are adjusted annually for inflation while the portfolio grows above inflation on average. The result is expressed in today’s purchasing power.

The FIRE number covers the years you fund yourself. From State Pension age (and any workplace or private pension access) those incomes reduce how much your portfolio must cover.

Lean FIRE (minimal expenses), Fat FIRE (comfortable living), Coast FIRE (enough invested to stop adding) and Barista FIRE (part-time work covering some expenses).