Your coast FIRE number is the amount that, left untouched and compounding at your real return, grows to fund retirement at your target age with no further contributions. Enter your numbers to see it, whether you have reached it, and the age you start coasting.
Your coast FIRE number is $478,294
At $120,000 today you are $358,294 short. This is the amount that, left untouched at a 3.9% real return, grows to your $1,500,000 FIRE number by age 65.
FIRE number (at retirement)
$1,500,000
$60,000 / 4.0%
Real rate of return
3.9%
7.0% nominal − 3.0% inflation
You coast from age
—
Not reached by age 100 at this return
This calculator answers one question. The app models your whole retirement.
Coast FIRE is one milestone on a longer path. 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 freeCoasting means your retirement saving is done: your existing balance will grow on its own to cover retirement, so any income from here only needs to cover today's living costs. The number has two parts.
First, the FIRE number — the portfolio that funds your spending indefinitely at a safe withdrawal rate:
FIRE number = annual spending / safe withdrawal rate
At a 4% rate that is 25 times your annual spending. The 4% rate comes from the Trinity study (Cooley, Hubbard and Walz, 1998), which tested historical withdrawal rates and found 4%, adjusted for inflation each year, lasted 30 years in nearly every period.
Second, discount that target back to today at your real return over the years until retirement:
coast FIRE number = FIRE number / (1 + real return) ^ years to retirement
The real return removes inflation so the whole calculation stays in today's dollars: real return = (1 + nominal return) / (1 + inflation) - 1. At a 7% nominal return and 3% inflation, that is about 3.9%. A 35-year-old targeting $60,000 of spending at a 4% rate has a $1.5M FIRE number and a coast number near $478,000 at 65 — reach that once and compounding does the rest.
Working part-time in retirement? Use the barista FIRE calculator. Want the full target on its own? See the FIRE number calculator. To turn a portfolio into income, use the 4% rule calculator, and to solve for a retirement date at your current savings rate, use the when can I retire calculator.