Coast FIRE calculator

Find the age when your existing investments can take over and you can stop making retirement contributions. JMM shows a range because one assumed return does not produce one certain date.

Worked example — You could stop contributing between: 41 and 63. $180,000 invested today, $1,500/month, targeting $1,400,000 by 65, real terms

FIRE plan: stage 2 of 4

Choose the path

Keep contributing, let compounding take over, or bridge part of spending with work.

See all four FIRE stages

Try:

Mid-career: The page's own default: a saver checking whether existing momentum alone gets them there.

Your timeline

Your ageRetire at

What you have and add

Invested today$Contributing monthly$

What retirement needs to cover

Set my target using

Retirement target, today's dollars$

Advanced options 6

Expected yearly return, before inflation%Investment growth before rising prices reduce buying power.Annual inflation%Return range around your estimateptsThe calculator tests this many percentage points above and below your return estimate.Share in tax-deferred accounts%The share held in accounts such as an RRSP, 401(k), or traditional IRA where withdrawals may be taxed.Expected tax rate when withdrawn%

Tax-deferred means RRSP, 401(k) or traditional IRA. Treat TFSA and Roth balances as tax-free here. Taxable accounts are simplified and do not model annual dividends, capital gains or adjusted cost base.

Try stopping at age

Your resultYou could stop contributing betweenYou could stop contributing between: 41 and 63. 50 years, 1 month at your base case

What this means: The later age is the safer planning date. The earlier age needs the more optimistic return.

Uses growth after inflation and reduces tax-deferred savings by the withdrawal tax rate you entered.

Main limit: Returns are assumptions, not a promised path. A small return change can move the Coast FIRE age by years.

Next: Plan from the later age in the range, then change the monthly contribution if that date is too late.

See the exact return and tax adjustment

After compounding inflation with the entered return, the working return is 4.39%, not the 4.50% produced by simple subtraction. The target is post-tax spending money, so 60% of the balance is reduced by the 18% withdrawal tax rate entered above.

The two ages come from recomputing the answer across a 2 point band on the return assumption, and across that band the coast age moves by 21.2 years. That is the honest output of this calculation. A single coast age quoted without that range is a guess wearing the costume of a milestone, and it is what every other coast calculator prints.

Balance after the tax haircut$160,560

If you stopped today$608,268

Target in the dollars of 65$3,010,009

What changes now?

Coast number today: $369,548
The balance that would reach $1,400,000 by 65 on compounding alone, with no further contribution, at your base return assumption.
If you stop at age 45: $1,990 a month
Contribute that in today's dollars until 45, which is 133% of what you contribute now, then stop and let compounding finish the job by 65. Stopping that early costs more per month than your current plan.
One more year of aggressive saving: about 1.5 years
Under these assumptions, one more year of contributions moves the estimated Coast FIRE range forward by about 1.5 years, compared with pausing for the next twelve months and resuming after. At the pessimistic end of the band, pausing the year would push the plan past 65 entirely.

The coast number is the target divided by (1 + real return) raised to the years left, so it is an exponential in a number nobody knows. Over three decades a small change in the exponent is a large change in the answer, which is why the band is the output and the middle row is only one of three defensible answers.

What is Coast FIRE?

Coast FIRE is the balance at which existing savings alone, with no further contribution, reach your retirement target by compounding alone. Below that balance, contributions are still doing real work; at or above it, you could stop contributing today and still arrive on time.

The target itself is annual spending divided by a withdrawal rate. The FIRE number calculator states that target at the commonly compared rates and tests how long the balance actually funds the spending once you arrive.

Coast FIRE number by age and target

The coast number at a $1,400,000 target, 7% nominal return and 2.5% inflation, retiring at 65. The balance needed falls every year, because there are fewer years left for it to compound.

Current age	Coast number today
25	$251,033
30	$311,194
35	$385,772
40	$478,223
45	$592,829

Why this differs from every other coast calculator

Coast calculators almost universally apply a nominal return, usually 7%, to a target stated in today's dollars. That is a units error, and it flatters the result by the entire inflation path. Everything here is solved in real terms with the exact Fisher relation, the coast age is reported as a range across a band of return assumptions rather than a single guessed number, and a tax haircut is applied to whatever share of the balance sits in a pre-tax account. Read the pessimistic end of the range first: if the plan only coasts at the optimistic end, it does not coast.

What this does not model:

One constant real return, applied smoothly, with no volatility and no sequence-of-returns risk.
No taxes on the way up, no fees, no employer match, and no contribution limits.
No change in the target itself between now and retirement.
A single blended tax rate on withdrawals, not a real bracket structure.

The next question after this one

Sequence of returns risk calculatorCalculatorThe coast range assumes returns compound smoothly. Stress-test what a bad first decade does before treating the coast date as settled.Open next

What Pro adds here

Account-by-account tax treatment, contribution limits, and a coast age distribution instead of a band are Pro features. The launch list sends one email at launch.