Coast FIRE Calculator

See whether you have saved enough to stop investing and still retire on time, and when you will reach Coast FIRE.

Assumptions reviewed

years
years
$
$
$
% / yr
% / yr
%
47% of the way to Coast FIRE
Coast FIRE number today
$318,862

Keep investing $1,500 a month until about age 41.7, then you can coast.

Coast FIRE number vs your portfolio
Coast FIRE numberKeep investingStop investing now
$0$500K$1M$1.5M3034384246505458Coast at 41.7Age
Status
47% of the way there
Still needed to coast
$168,862
You reach Coast FIRE at age
41.7 years old
Full FIRE number at retirement
$1,000,000
Projected at retirement if you stop now
$470,422
At retirement age
$0$500K$1M$1.5MNeeded — Portfolio: $1,000,000NeededStop now — Portfolio: $470,422Stop nowKeep investing — Portfolio: $1,478,029Keep investing
Show the working
  1. FIRE number = $40,000 ÷ 4% = $1,000,000
  2. Real return = (1 + 7%) ÷ (1 + 3%) − 1 = 3.88%
  3. Coast FIRE number = $1,000,000 ÷ (1 + 3.88%)^30 = $318,862
  4. Your $150,000 grows to $470,422 by 60 with no more contributions

Runs entirely in your browser. Nothing you enter is uploaded.

Formula

FIRE number = retirement spending ÷ withdrawal rateCoast FIRE number = FIRE number ÷ (1 + real return)^(years to retirement)

How it works

Coast FIRE is the point where you have invested enough that you never need to add another dollar for retirement. Compounding takes your current portfolio the rest of the way to your full FIRE number by the age you choose. From then on you only need to earn enough to pay your bills.

The Coast FIRE number is your full FIRE number, discounted back to today at your real return. The younger you are, the smaller it is: a 25-year-old aiming to retire at 60 needs far less invested than a 45-year-old with the same goal, because the money has 35 years to grow instead of 15.

The chart shows how the requirement rises each year — the curve climbs because there is less time left to compound — alongside your portfolio if you keep investing and if you stop today. Where your portfolio crosses the curve, you can coast.

Coast FIRE vs Barista FIRE

Both involve working after you have built a large portfolio, but in different ways. With Coast FIRE you do not touch your investments at all — your job covers all your spending until retirement age. With Barista FIRE you start withdrawing early and work part-time to cover only the shortfall.

Coast FIRE suits people who like their work but want the freedom to switch to a lower-paying, lower-stress job, take a sabbatical, or go part-time without derailing retirement.

Risks to keep in mind

Coasting puts more weight on future returns. A poor decade of markets right after you stop contributing can leave you short at retirement age, so build in a margin — use a lower expected return or keep investing a little after you reach the number.

Frequently asked questions

What does "coasting" actually mean?

You stop saving for retirement and spend everything you earn. Your existing investments stay invested and grow on their own. You still need income to cover today's living costs.

What retirement age should I use?

Use the age you would like full financial independence. Traditional plans use 60–67; using an earlier age makes Coast FIRE harder to reach because there is less time to compound.

Is the Coast FIRE number in today's dollars?

Yes. The calculator uses your real return (return minus inflation), so every figure is in today's purchasing power.

Should I count retirement accounts I cannot touch until 59½?

Yes — Coast FIRE is about reaching your goal by a traditional retirement age, when those accounts are available without penalty.

Sources

  • Bengen, W. P. (1994). "Determining Withdrawal Rates Using Historical Data." Journal of Financial Planning.
  • Cooley, Hubbard & Walz (1998). "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable." AAII Journal (the "Trinity study").
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