Coast FIRE Calculator

Find out whether your investments could already grow to a full retirement on their own - and if not, the age at which you could stop saving for good.

Where your coast money lives matters

A low-cost brokerage account with cheap index funds is the workhorse of every Coast FIRE plan - high fees quietly push your coast age years later.

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How Coast FIRE works

Your FIRE number is the portfolio that can sustain your retirement spending - commonly estimated as 25× annual spending, based on the 4% rule. Coast FIRE asks a gentler question: how much would you need invested today so that compound growth alone gets you there by retirement age, with no further contributions? That amount is your coast number, and it is often surprisingly small when retirement is decades away.

Coast number = (Annual spending × 25) ÷ (1 + r)^{years to retirement}

If your portfolio is already at or above the coast number, every dollar you save from here on is a bonus, not a requirement. If you are not there yet, this calculator projects your portfolio forward with your monthly contributions and finds the age at which it crosses the (steadily rising) coast threshold - the age at which you could stop saving entirely and still retire on schedule.

Frequently asked questions

What is Coast FIRE?

Coast FIRE means you already have enough invested that compound growth alone - with no further contributions - will carry your portfolio to your retirement target by your traditional retirement age. You still work to cover your living expenses, but saving for retirement becomes optional.

How is Coast FIRE different from regular FIRE?

Regular FIRE means your portfolio can fund your spending right now, so you can stop working entirely. Coast FIRE is an earlier milestone: you can stop saving, but you keep working to pay the bills while your investments grow untouched.

What return should I assume?

Use a real (after-inflation) return, because your spending target is in today's dollars. A real 5-7% is a common assumption for a stock-heavy portfolio; picking the lower end builds in a margin of safety.