Coast FIRE calculator

age
$
$
$
%
age
You can stop saving at
age 38

then growth alone reaches $1.2m by 65

Coast bar today$218k
You hold55% of it
Stop saving, age 38Your number $1.2mStop, age 38$1.2m

Your pot, month by month: saving until the marked age, coasting after. The dashed line is your number.

Wanting $48.0k a year from age 65 needs a number of $1.2m. At age 30, $218k invested today reaches it with nothing added after, compounding at 5.0%. You hold $120k.

How to use this, and the parts people get wrong
  • Coast means you stop adding money and let the pot grow on its own until retirement.
  • The two ages do different jobs: your age now starts the clock, retirement age ends it.
  • If the answer says you have already coasted past the line, the remaining question is only whether the return assumption holds.

Where the bar sits today

To coast from today you would need $218k already invested. Keeping up $1200 a month, compounding takes over at age 38.

$1.2myour number at 65
$48.0kthe yearly spending it assumes
27 yearscompounding does the last stretch alone

The coast bar at every age

What has to be invested already, by age, for compounding alone to finish by 65.

AgeCoast barOf your number
25$170,45514% of your number
30$217,54818% of your number
35$277,65323% of your number
40$354,36330% of your number
45$452,26738% of your number
50$577,22148% of your number
55$736,69661% of your number
60$940,23178% of your number

Questions people ask

What is Coast FIRE?
The point where your invested savings, left alone, will grow into your retirement number by retirement age. Past it you still work and spend, but you no longer have to save.
How is the coast number worked out?
Your number is 25x your planned yearly spending (the 4% convention). Today's coast bar is that number discounted back at your growth rate: $218k at age 30 on the seeded figures.
What growth rate should I use?
A real, after-inflation figure keeps everything in today's money; 5% is a common middle. The bar moves a lot with this choice, which is the honest reason to try a range rather than trust one decimal.
Does coasting mean retiring early?
No. It means the SAVING can stop, not the working. Your job then only has to cover the life you live now.
What if I am past the bar already?
Then compounding alone reaches your number by your date, and every further dollar saved brings the date closer instead.

Method and sources

  • Standard compound-growth arithmeticMonthly simulation against a discounted target
The calculation

Your number is 25x planned yearly spending. The coast bar at any age is that number discounted back at your growth rate. The coast age runs your pot forward month by month with your saving until it first clears the rising bar; after that point the projection carries no further contributions.

What these figures do not cover
  • The 4% rule is a convention, not a guarantee; a colder withdrawal rate raises every bar.
  • Returns are assumed steady; real sequences wobble around the average.
  • Taxes on the way out depend on your accounts and country and sit outside this arithmetic.

Last updated July 2026.

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