Coast FIRE calculator
The balance at which compounding finishes the job alone — weighed against what you actually hold, and dated to the year you cross it.
Coast FIRE number
$231,377
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Why the line rises as you stand still
coast number = target ÷ (1 + r)years left Coast FIRE is the same target seen from further back. Thirty years of 5% real growth turns a dollar into about $4.32, so a million-dollar target needs roughly $231,000 today. Wait ten years and the same target needs about $377,000 — the coast number rises every year you do not reach it, because the compounding you were counting on has less time to run.
That is why the date on this page is not simply “when does my balance hit today’s coast number.” You are chasing a moving line. Dividing both sides by the growth you have both accrued collapses the chase back to a fixed comparison, which is what the calculator solves:
P + PMT × (1 − (1+r)−t) ÷ r ≥ coast number It also shows plainly when the answer is never. Contributions are worth at most PMT÷r no matter how long you keep making them, so a gap wider than that never closes — the calculator says so rather than printing a date you would never reach.
Assumptions on the counter
- A real return net of inflation; every figure stays in today’s dollars.
- Constant annual compounding — no sequence-of-returns risk modeled, which is precisely the risk that makes coasting on nothing but growth uncomfortable.
- Contributions stop the day you reach the line. Most people who get here keep saving anyway.
- No taxes, employer match, Social Security, or account-type differences.
Questions people ask
What is Coast FIRE?
The point where the money you have already invested will compound into your full FIRE number by your target date without another dollar added. You still work and still cover your own expenses — but nothing you earn from then on has to go toward retirement.
How is the Coast FIRE number calculated?
It is your FIRE number discounted backwards over the years remaining: coast number = target ÷ (1 + real return)^years left. Thirty years of 5% real growth multiplies money about 4.3×, so a $1,000,000 target needs roughly $231,000 invested today.
Why does my Coast FIRE number go up as I get older?
Because there is less time left for compounding to do the work. The same target discounted over 20 years instead of 30 is a much larger number. This is the part most people miss: the line you are chasing rises every year you do not reach it, which is why the calculator solves for when your balance crosses the moving line rather than today’s static one.
Can I really stop saving once I hit it?
Arithmetically yes, on these assumptions. In practice it is a decision to hand your entire retirement to an assumed rate of return with no further deposits to smooth a bad decade. Most people who reach it keep saving something — Coast FIRE is more useful as permission to take the lower-paying job than as an instruction to stop.
What is the difference between Coast FIRE and Barista FIRE?
Coast FIRE means your investments are done growing on their own but you still cover your living costs from full-time work. Barista FIRE means you have enough that part-time work only needs to cover part of your spending, with the portfolio covering the rest.