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FIRE Number Calculator

Calculate the portfolio multiple of spending needed for financial independence.

About FIRE Number Calculator

Dropping the withdrawal rate from 4% to 3% raises the multiple from 25 to 33 times spending, which is a third more capital. The inflation-adjusted figure shows the same target expressed in the money of the year you actually retire. Small changes in the assumed withdrawal rate move the target enormously, which is why the multiple matters more than any projection of returns.

Formula

FIRE Number

FIRE number = annual expenses × (100 ÷ withdrawal rate)

expense multiple
The reciprocal of the withdrawal rate, 25 at 4%

Worked example

With the default values below, FIRE Number Calculator returns FIRE Number in Today’s Money of $1,000,000.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Annual spendingminimum 0
40,000
Safe withdrawal rateaccepts 0–100 %
4 %
Expected inflationaccepts 0–100 %
2.5 %
Years until you stop workingaccepts 0–50 years
15 years

Results

FIRE Number in Today’s Money
$1,000,000.00
Multiple of Annual Spending
25.0 x
Target in Future Money
$1,448,298.17
Annual Spending at Retirement
$57,931.93
Monthly Income Supported
$3,333.33

Step by step

  1. 1Values used
  2. 2FIRE Number
  3. 3FIRE Number in Today’s Money= 1,000,000.00
  4. 4Multiple of Annual Spending= 25.0 x
  5. 5Target in Future Money= 1,448,298.17
  6. 6Annual Spending at Retirement= 57,931.93
  7. 7Monthly Income Supported= 3,333.33

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take tax into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is FIRE Number calculated?

FIRE number = annual expenses × (100 ÷ withdrawal rate) Dropping the withdrawal rate from 4% to 3% raises the multiple from 25 to 33 times spending, which is a third more capital. The inflation-adjusted figure shows the same target expressed in the money of the year you actually retire.

Why does FIRE Number matter?

Small changes in the assumed withdrawal rate move the target enormously, which is why the multiple matters more than any projection of returns.

What values do I need to enter?

This calculator takes 4 inputs: Annual spending, Safe withdrawal rate, Expected inflation, Years until you stop working. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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