Coast FIRE Calculator

Find out if you can stop saving and let your investments grow to retirement on their own.

Current Savings ($)

Current Age

Retirement Age

Monthly Expenses ($)

Annual Return (%, after inflation)

5% is close to the 5.2% real return of world equities since 1900.

Withdrawal Rate (%)

4% rule standard.

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What Is Coast FIRE?

Coast FIRE is the point at which your invested portfolio is already large enough that, left completely alone, compound growth will carry it to your full FIRE number by traditional retirement age. You never have to contribute another dollar to retirement savings again.

That does not mean you stop working. It means you stop saving. From that moment, you only need to earn enough to cover your current living expenses, because your future is already funded. Everything above that line is yours to spend, and every career decision stops being a financial decision.

This is what makes Coast FIRE the most reachable milestone in the FIRE movement. Full financial independence can take twenty years of aggressive saving. Coast FIRE often arrives in your early thirties, and it changes your life immediately.

The Coast FIRE Formula

Coast FIRE works backwards from the number you will eventually need, then discounts it by the years of compounding you have left:

Coast FIRE Number = FIRE Number / (1 + r)ⁿ

FIRE Number — your annual retirement spending divided by your withdrawal rate. At a 4% rate, that is your spending multiplied by 25.
r — your expected annual return after inflation. This calculator defaults to 5%, close to the 5.2% real return of world equities from 1900 to 2024.
n — the number of years between your current age and your target retirement age.

The exponent is what does the heavy lifting. Every extra year of compounding shrinks the amount you need today, which is why reaching Coast FIRE early is worth so much more than reaching it late.

A Worked Example

Take someone aged 32 who expects to spend $40,000 a year in retirement and plans to stop working at 65.

Annual retirement spending: $40,000

FIRE number (4% rule): $40,000 × 25 = $1,000,000

Years of compounding (65 − 32): 33

Real return assumption: 5%

Coast FIRE number: $1,000,000 / (1.05)³³≈ $200,000

Roughly $200,000 invested today, never touched again, grows to a million by 65. That is the entire idea. Someone who needs a million to retire fully needs about a fifth of it to stop saving for retirement altogether — provided they leave it alone for three decades.

When Coast FIRE Does Not Work

Coast FIRE is an elegant idea with real failure modes. It is worth knowing them before you rearrange your career around the number.

You touch the money. The entire model assumes the portfolio compounds undisturbed for decades. A withdrawal at year eight does not just remove that amount, it removes everything that amount would have become. Coast FIRE and a thin emergency fund are a dangerous combination.
Your spending grows. The number is anchored to the annual spending you assumed today. Children, a larger home, or a move to a more expensive city can raise your real FIRE number substantially, and your coast number with it.
Returns disappoint. A 5% real return is a long-run average, not a promise. A prolonged period of lower returns means arriving at 65 short of the target, with no contributions made in between to cushion it.
You want to retire early. Coast FIRE funds a traditional retirement age. If your goal is to stop working at 50, coasting will not get you there — you need to keep contributing.

What This Calculator Assumes

Every projection rests on assumptions. These are ours, stated plainly so you can judge the output for yourself.

Returns are constant and compound annually. Real markets do neither.
The return you enter is after inflation, so the resulting figure is in today's purchasing power.
No investment fees, platform costs, or taxes are deducted. Fees in particular compound against you over thirty years — see our investment fee calculator for how much they cost.
No further contributions are made after today.
Your retirement spending stays flat in real terms for the whole period.

This is an educational projection, not financial advice, and past returns do not predict future ones. Treat the output as a direction of travel rather than a guarantee.

Frequently Asked Questions

Does reaching Coast FIRE mean I can quit my job?

No. It means you can stop saving for retirement. You still need income to cover today's living costs. What changes is that the income requirement drops to your actual expenses, which opens up lower-paid, part-time, or more interesting work that was previously unaffordable.

What return rate should I use?

5% after inflation is our default. World equities returned 5.2% real from 1900 to 2024 (Dimson-Marsh-Staunton). US-only equities returned 6.6%, which is where the familiar 7% figure comes from. Run the calculator at several rates — if the answer changes your decision, the plan is too fragile.

How is this different from Barista FIRE?

Coast FIRE means your portfolio is fully self-funding and you never draw on it before retirement. Barista FIRE means you draw on a partially funded portfolio while working part-time to cover the gap, often for the health benefits. We compare both in detail in Coast FIRE vs Barista FIRE.

Should I include my house in the calculation?

Only invested assets belong in this number. A primary residence does not generate withdrawable income, so counting it inflates your position. Include retirement accounts and taxable brokerage holdings; leave out your home and your emergency fund.

What happens if I keep investing after hitting Coast FIRE?

You move toward full FIRE and an earlier retirement date. Coast FIRE is a floor, not a ceiling — many people hit it, downshift to less demanding work, and keep contributing at a reduced rate. Use our time to FIRE calculator to see how much earlier that gets you there.

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