Coast FIRE Calculator
See whether your current investments, left to compound with no further contributions, will reach your retirement target. If they will, you have hit "Coast FIRE" — you only need to cover living costs, not keep saving for retirement.
How it works
What Coast FIRE means
Coast FIRE is the moment your retirement savings reach escape velocity. You have invested enough that, even if you never add another dollar, compounding alone should carry that balance to your full FIRE number by the time you retire. You still need income to cover today's expenses, but you no longer need to save for old age.
How the number is derived
It is a future-value calculation run in reverse. Your coast number is target ÷ (1 + return)^years, where years is the time left until retirement. Example: if your target is $1,000,000, retirement is 30 years away, and you assume a 6% annual return, then 1.06^30 is about 5.74, so your coast number today is roughly $174,000. Invest that much now and it should grow to the target untouched.
How to read your result
If your projected value meets or beats the target, you have reached Coast FIRE. If not, the shortfall tells you how much more invested capital you still need today.
Caveats
- The return is an assumption, not a promise.
- Coasting still means covering living costs another way.
- Use a real, after-inflation return and a target in today's money.
- A weak market early on can derail the plan.
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Frequently Asked Questions
What exactly is Coast FIRE?
It is the point where you no longer need to save for retirement: the money you have already invested will compound on its own to reach your target by retirement age. From then on you only need to cover current expenses.
How is it different from regular FIRE?
Regular FIRE means you have enough to stop working now. Coast FIRE is an earlier milestone: retirement saving is "done", and you only need to earn enough to cover living costs for a while.
What return rate should I use?
A common long-run stock assumption is 5-7% nominal. To be conservative, use a real (after-inflation) return such as 4-5% and set your target in today's purchasing power.
Once I hit Coast FIRE, can I stop working?
No. Coast FIRE only frees you from saving for retirement. You still need enough income to cover current living costs until you actually retire, because the invested balance is left untouched to keep compounding.
What happens if returns fall short of my assumption?
Then the balance may not reach the target, and you would need to resume saving or delay retirement. Because early weak years hurt the most (sequence risk), it is wise to recheck your numbers every year or two.
Are taxes and fees included?
No. The calculator shows a gross projection. Investment fees and taxes on gains reduce real outcomes, so treat the result as an optimistic ceiling and shade your assumed return downward to stay safe.
This calculator is an educational estimate, not individual financial advice. It does not account for taxes, fees, or inflation. Results depend heavily on the assumed return.