Coast FIRE Calculator
Have you saved enough that your investments alone will carry you to retirement, even if you stopped adding to them? Enter your age, target retirement age, current assets and spending, and this tool returns your Coast FIRE number, whether you have reached it, and the age you will. The output is arithmetic on the assumptions you enter. Nothing you enter is stored.
Last updated August 30, 2026
How it works
Coast FIRE is the point where your existing investments, left alone to compound, would grow into your full retirement target by the time you retire, without another dollar saved. First the tool finds your retirement target, your annual spending divided by your withdrawal rate. Then it discounts that target back to today at your expected real return over the years until retirement. That discounted figure is your Coast FIRE number. If your current assets already exceed it, further saving is optional to retire on schedule; your money coasts the rest of the way.
A worked example
Take someone aged 35 who wants to retire at 65, spends $80,000 a year and uses a 4 percent withdrawal rate, so their retirement target is $2,000,000. At a 5 percent real return over 30 years, the Coast FIRE number today is about $463,000. With $200,000 invested they have not reached it yet, but if they keep saving, the tool shows the age at which their balance will overtake the coasting threshold, after which they could stop saving and still land on target.
Why Coast FIRE is a useful milestone
It reframes independence as a moment that arrives well before retirement. Hitting your Coast FIRE number does not mean you can stop working; it means the saving part is done, and anything you earn from then on is for living, not for the future. For a lot of people that is a more motivating and more reachable target than the full number, and it is worth knowing when you cross it.
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Frequently asked questions
What is the difference between Coast FIRE and FIRE?
FIRE is having enough to live off your investments now. Coast FIRE is having enough that, without adding another dollar, your investments will grow into your FIRE number by retirement. Coast FIRE arrives earlier and only requires that you stop saving, not that you stop working.
Does reaching Coast FIRE mean I can retire?
No. It means you no longer need to save for retirement, because your existing investments will get there on their own by your target age. You still need income to cover living costs until then.
How sensitive is it to the return assumption?
Very. The Coast FIRE number is your target discounted over many years, so a small change in the expected real return moves it noticeably. That is why the return is a field, and why the result is arithmetic on your assumption, not a prediction.
Is my data stored?
No. The calculation runs entirely in your browser. Nothing you enter is saved or sent anywhere.