FIRE Calculator
The portfolio needed for financial independence and how long it takes to reach — with the savings rate that actually drives the answer.
The FIRE number is annual spending divided by a safe withdrawal rate, usually 4%.
How the fire calculator works
The FIRE number is annual spending divided by a safe withdrawal rate, usually 4%. At 4%, that is 25 times your spending.
What determines the timeline is not income or returns but the *savings rate* — the share of take-home pay you do not spend. Saving 50% gets you there in about 17 years from zero regardless of the absolute numbers, because a higher savings rate both grows the pot faster and shrinks the pot you need.
Formula: FIRE number = annual spending / withdrawal rate
Worked examples
| Inputs | FIRE number | Note |
|---|---|---|
| 90k income, 50k spending | $1,250,000.00 | 1.25m target, 44% savings rate |
| Spending less | $1,000,000.00 | a lower target AND a higher savings rate |
| A modest savings rate | $1,875,000.00 | decades away |
FAQFrequently asked questions
What is the FIRE number?
The portfolio that supports your spending indefinitely — annual spending divided by a safe withdrawal rate, so 25× at 4%.
Is the 4% rule reliable?
It came from US historical data over 30-year retirements. For a longer retirement, or outside the US, many planners use 3 to 3.5%.
Why does the savings rate matter more than the return?
Because it works from both ends: saving more grows the portfolio faster and, by spending less, shrinks the target.
What is Coast FIRE?
Having enough invested that it grows to your number by retirement age without further contributions. This page shows the ten-year version.
Does it account for tax or pensions?
No. It is the underlying arithmetic. Real planning has to account for how the money is taxed and when access to retirement accounts begins.
Where these figures come from
- CFA Institute — Quantitative Methods: The Time Value of Money — the discounting, annuity and IRR conventions used here
- US Federal Reserve — Regulation Z (Truth in Lending), APR calculation — why APR includes fees where a nominal rate does not
- ASIC MoneySmart — the Australian regulator's own consumer calculators
Last checked: September 2026. These are the standard textbook formulas; the conventions named are those of the CFA Institute curriculum and ISO 80000 usage.