Your FIRE number is your annual spending divided by your safe withdrawal rate — 25 times spending at a 4% rate. Enter your budget to see the target, plus lean and fat variants so you can see how spending changes the number.
Your FIRE number is $1,500,000
That is 25.0× your $60,000 annual spending. At a 4.0% withdrawal rate, a $1,500,000 portfolio funds $60,000 a year, adjusted for inflation, with a high chance of lasting 30 years.
Lean FIRE
$900,000
$36,000 / yr
Your FIRE
$1,500,000
$60,000 / yr
Fat FIRE
$2,400,000
$96,000 / yr
This calculator answers one question. The app models your whole retirement.
Your FIRE number is a target, not a plan. CoastIQ runs tax-accurate projections with Monte Carlo simulation, Roth conversion analysis, and Social Security timing, all on-device with no data collection. Free to start on iPhone.
Get CoastIQ freeThe formula is one division:
FIRE number = annual spending / safe withdrawal rate
At a 4% withdrawal rate this equals 25 times your annual spending, because 1 divided by 0.04 is 25. The 4% rate comes from the Trinity study (Cooley, Hubbard and Walz, 1998), which found that a portfolio of stocks and bonds withdrawing 4% in year one, then rising with inflation, lasted 30 years in nearly every historical period. A more cautious 3.5% rate gives a multiple near 29; a more aggressive 5% rate gives 20.
The number is in today's dollars, so enter spending in today's dollars. Because the 4% rule already builds in annual inflation adjustments to your withdrawals, you do not multiply the target itself by inflation.
These are the same formula with different spending. The calculator shows a lean figure at 60% of your budget and a fat figure at 160%, so you can see how much a leaner or richer lifestyle moves the target. A $24,000 lean budget needs $600,000; a $96,000 fat budget needs $2.4M.
To find what you need saved today to coast to this number, use the coast FIRE calculator. If part-time work will cover some spending, use the barista FIRE calculator. To turn a portfolio into a withdrawal, use the 4% rule calculator, and to find your retirement date, use the when can I retire calculator.