FIRE Calculator
Enter your annual spending, how much you save each month, your expected return, and a safe withdrawal rate to see the target portfolio you need for financial independence (FIRE) — and how long it takes to get there.
How it works
What the FIRE number is and how it is derived
Your FIRE number is the portfolio large enough to fund your lifestyle indefinitely from investment returns. It is calculated as annual spending divided by your safe withdrawal rate. At a 4% rate the arithmetic is simply 100% / 4% = 25 times your yearly spending, so spending of 40,000 implies a target of 1,000,000. A lower rate such as 3.5% raises the multiple and the target.
How to read your result
The headline figure is the portfolio you are aiming for. The time-to-reach estimate grows your current balance plus monthly savings with monthly compounding until it meets that target. A higher savings rate or expected return shortens the timeline far more than small cuts to spending.
Key caveats
- The 4% guideline comes from US historical research, namely Bengen (1994) and the 1998 Trinity Study, and is a planning rule of thumb rather than a guarantee.
- Return and withdrawal rates are assumptions; real markets vary from year to year.
- The model ignores taxes and inflation, so leave a margin and revisit the numbers as your situation changes.
Read next
How financial independence (FIRE) actually works →
Run the compounding numbers: how monthly contributions grow through compounding →
Frequently Asked Questions
How is the FIRE number calculated?
It is your annual spending divided by a safe withdrawal rate. At the common 4% rate that equals 25 times your yearly expenses, because 100% divided by 4% is 25.
Where does the 4% rule come from?
It traces to US historical research by William Bengen in 1994 and the 1998 Trinity Study, which tested withdrawal rates against past market returns. It is a planning guideline based on that data, not a promise.
Why is the multiple 25 times spending?
Because 25 is the inverse of 4%. If you instead assume a 3.5% rate the multiple rises to about 29, and at 5% it falls to 20, so the target moves with the rate you choose.
Does it account for inflation?
For simplicity it does not. In reality your expenses rise over time, so it is safer to base the target on future spending or to leave a margin.
How accurate is the time to reach it?
It is an estimate that assumes a constant annual return and steady savings. Real markets fluctuate, so treat the number as a guide rather than a firm date.
Should I use a lower withdrawal rate?
A more cautious rate such as 3% or 3.5% raises your target but adds a buffer against weak markets and longer retirements. The right choice depends on your horizon and risk tolerance.
This calculator is an educational estimate, not individual financial advice. It does not account for taxes, inflation, or return variability.