FIRE Number Calculator (4% Rule)
FIRE calculator: how much you need invested to retire early, from annual expenses and a safe withdrawal rate (4% rule).
N = Ew
How to use this calculator
- Choose the quantity you want under “Solve for”.
- Type the known values and pick their units: any combination works.
- The result updates as you type. Open “Show the steps” to see the substitution.
The 4 % rule says a diversified portfolio can usually fund withdrawals of 4 % of its starting value a year, adjusted for inflation, for about 30 years. Your FIRE number is therefore annual expenses ÷ 0.04, or 25× expenses.
For retirements longer than 30 years, many planners use 3–3.5 %. Use the savings calculator to see how long it takes to get there.
Formula
N = Ew
| Symbol | Quantity | Units |
|---|---|---|
| E | Annual expenses | $, €, £ |
| w | Safe withdrawal rate | %, × |
| N | Portfolio needed | $, €, £ |
Worked example
Given: E = 40,000.00 $ · w = 4 %
N = Ew
Result: N = 1,000,000.00 $
Frequently asked questions
How much do I need to retire on $40,000 a year?
40,000 ÷ 0.04 = $1,000,000.
Where does the 4 % rule come from?
From studies of historical US stock and bond returns, notably the Trinity study, which found 4 % withdrawals survived most 30-year periods.