Coast FIRE Calculator

Coast FIRE is the moment your invested savings are large enough that, even if you never contribute another cent, compound growth alone will carry them 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. It is the point where your future is already funded and your money coasts the rest of the way.

First we set your FIRE number - your annual retirement spending divided by your safe withdrawal rate (spending × 25 at 4%). Then we discount it back to today at your expected real return: coast number = FIRE number ÷ (1 + return)^years to retirement. If your current savings already exceed that, you are Coast FIRE. Everything is in real, inflation-adjusted terms.

The rising "coast target" line is how much you would need at each age to still coast to your FIRE number by retirement - it climbs because less time means less compounding. The "your savings" line is your projected balance including your monthly contributions. Where your savings cross above the target is your Coast FIRE age: from then on, you could stop saving entirely.

Because compounding needs time. At 30 with 35 years to grow, a modest sum can balloon into your FIRE number, so the coast target is low. At 55 with only 10 years left, that same growth barely happens, so you need far more upfront. Starting early is powerful precisely because it lowers the bar to coast.

No - and that is the point. Coast FIRE means retirement is funded, but you still need income to cover current living costs until you actually retire. It is a milestone of freedom: you can downshift to a lower-paying but more enjoyable job, take career breaks, or stop retirement saving, knowing the compounding is already done.

Yes. Alvest follows your real, after-inflation net worth across every account and asset, and projects it forward toward milestones like Coast FIRE and full financial independence. You can start free.