This solves for the age you reach financial independence at your current savings rate. Enter your assets, monthly contribution, and target spending, and it projects forward to the year your portfolio can fund your spending for good.
You can retire at age 66 yr 8 mo
That is 31.7 years away. Contributing $1,500 a month on top of $120,000 today, at a 3.9% real return, your portfolio reaches its $1,500,000 FIRE number then.
FIRE number
$1,500,000
$60,000 / 4.0%
Real rate of return
3.9%
7.0% − 3.0%
Projected balance at 65
$1,383,945
If you keep this rate
This calculator answers one question. The app models your whole retirement.
This uses one flat return; real markets vary year to year. 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 freeFirst, the target. Your FIRE number is the portfolio that funds your spending at your safe withdrawal rate:
FIRE number = annual spending / safe withdrawal rate
At a 4% rate, from the Trinity study, that is 25 times spending. Then the calculator grows your money forward. Each month it multiplies your balance by the monthly real return and adds your contribution, and it reports the first age the balance reaches the FIRE number:
balance next month = balance × (1 + monthly real return) + monthly contribution
The real return keeps the projection in today's dollars, real return = (1 + nominal return) / (1 + inflation) - 1, which is how the CoastIQ app treats inflation-adjusted contributions and spending. At a 7% nominal return and 3% inflation, the real return is about 3.9%.
Your savings rate moves the date more than your return does, because it works on both sides: a higher rate grows the portfolio faster and, if it comes from spending less, shrinks the FIRE number you are aiming at. Someone saving $1,500 a month reaches the target years earlier than the same person saving $1,000, holding everything else equal.
To see the smaller milestone of no longer needing to save, use the coast FIRE calculator. For part-time income in retirement, use the barista FIRE calculator. To size the target on its own, use the FIRE number calculator, and to turn a portfolio into income, use the 4% rule calculator.