Coast FIRE Calculator
Find out how much you need invested today to stop saving for retirement — and still arrive on time.
Compute your Coast FIRE number: the inflation-adjusted lump sum that compounds to your FIRE target by your retirement age with no further contributions.
What Coast FIRE means
Coast FIRE is the moment your retirement savings are basically done — not because you've saved the whole number, but because what you already have will grow on its own to cover retirement by the time you get there. You still work to pay today's bills, but you no longer have to save for retirement. Compound growth coasts you the rest of the way.
Your Coast FIRE number is the lump sum you'd need invested today to make that true. It's always smaller than your full retirement number, because decades of growth do the heavy lifting. Try moving your retirement age or return rate above and watch the number shift — every extra year of growth lowers what you need today. See how a single lump sum grows with the Compound Interest Calculator, or plan the full picture with the Retirement Calculator.
Coast FIRE separates two questions most retirement math blends together: "how much do I need at retirement" and "how much do I need now." The first is your FIRE number — annual spending divided by your withdrawal rate. The second discounts that target back to today at your inflation-adjusted return.
Because the calculator works in real (inflation-adjusted) terms, every figure is in today's dollars — the Coast FIRE number is what you'd recognize as money now, not an inflated future figure. If your current investments already exceed the Coast FIRE number, you've reached Coast FIRE: you can stop contributing and the portfolio is projected to reach your FIRE target on schedule. For the assumptions behind that growth, see the Compound Interest Calculator; to map drawdown and Social Security, use the Retirement Calculator.
Coast FIRE calculator: common questions
What is Coast FIRE?
Coast FIRE is the point where you have enough invested that, without adding another dollar, compound growth alone will carry your portfolio to your full retirement number by the time you retire. You still work to cover today's expenses, but you no longer need to save for retirement — your existing investments coast the rest of the way.
How is the Coast FIRE number calculated?
First the calculator finds your FIRE number — annual retirement spending divided by your withdrawal rate (4% by default, i.e. spending × 25). Then it discounts that target back to today using your inflation-adjusted (real) return over the years until retirement. The result is the lump sum you'd need invested now to coast: Coast number = FIRE number ÷ (1 + real return)^years.
What return and withdrawal rate should I use?
A common assumption is a 7% nominal return with 3% inflation (about 3.9% real), and a 4% withdrawal rate — the classic safe-withdrawal guideline. Use a lower return or higher withdrawal rate for a conservative stress-test. Because the calculator works in today's dollars, the result is already inflation-adjusted.
What's the difference between Coast FIRE and regular FIRE?
Regular FIRE means you have enough to stop working entirely. Coast FIRE is an earlier milestone: you have enough invested to stop saving for retirement, but you still work to cover current living costs. Your Coast FIRE number is always smaller than your full FIRE number because compound growth does the rest.
Is Coast FIRE the same as Barista FIRE?
They're related. Coast FIRE means your retirement savings are done and you only need to cover current expenses. Barista FIRE is a common way to do that — working a lower-stress or part-time job (often for the benefits) that covers living costs while your investments coast to full retirement.