What Is Coast FIRE?

Updated June 2026 · 6 min read

Coast FIRE is the moment your retirement basically takes care of itself. You've invested enough that, without adding another dollar, compounding alone grows your portfolio to a full retirement nest egg by the time you're 65. From that point on, you only need to earn enough to cover today's bills. You never have to save for the future again.

The "FIRE" in Coast FIRE stands for Financial Independence, Retire Early. But Coast FIRE is the gentlest version of it. You're not quitting work. You're removing the obligation to save, which is what makes most jobs feel like a trap. Once you hit your Coast number, a lower-paying, lower-stress job is suddenly enough, because it only has to pay this month's rent, not your entire future.

How Coast FIRE works

Normal FIRE asks: how big does my portfolio need to be so I can live off it forever? The standard answer is 25 times your annual spending (the 4% rule). If you spend $50,000 a year, your full FIRE number is $1,250,000.

Coast FIRE flips the question around. Instead of asking how much you need now to retire now, it asks: how much do I need now so that, if I never invest another cent, my money grows to that full number by traditional retirement age?

Because of compounding, the answer is much smaller than the full number. And the younger you are, the smaller it gets, because your money has more years to grow on its own.

A worked example

Say you're 30 years old, you spend $50,000 a year, and you plan to retire at 65. Your full FIRE number is $1,250,000. You expect a 7% real return, a common assumption for a stock-heavy portfolio after inflation. (When you open the calculator, set the return rate to this real figure. It uses nominal returns by default, so plugging in 8% gives a lower number.)

You have 35 years for compounding to work. Run the formula and the Coast number comes out to roughly $117,000. That's it. If you have about $117k invested at 30 and never add another dollar, history says it grows to ~$1.25M by 65.

Notice how the number shrinks the earlier you reach it:

Hit Coast at 30 instead of 45 and you need less than half as much. Most of the growth comes from time, not from the size of your starting pile. Every year you delay, compounding has less runway, so the target climbs.

Your return assumption matters more than the rest

The Coast number swings a lot depending on the return rate you plug in. Most calculators default to 7% real, which assumes the next few decades roughly rhyme with the last century of US market history. That's reasonable, but it isn't guaranteed.

The honest move: run your Coast number at 7%, 6%, and 5%, and treat the gap between them as your margin of error. Don't bet your freedom on a single optimistic input.

Coast FIRE vs Standard FIRE vs Barista FIRE

These three get mixed up constantly. The difference is simple once you see it side by side:

• Standard FIRE: you have the full 25× portfolio, so no job is ever needed. It's the largest target and usually the slowest to reach.
• Coast FIRE: you've saved enough to stop contributing. You still work to cover current expenses, but your retirement is already handled by compounding. Read more on the FIRE calculator homepage.
• Barista FIRE: you semi-retire now on a smaller portfolio, with part-time income permanently covering part of your spending (often for the health benefits). See the Barista FIRE calculator.

A common real-world path: hit Coast FIRE in your 30s, downshift to work you actually like, then drift toward full Standard FIRE as the portfolio keeps compounding in the background.

When Coast FIRE makes sense (and when it doesn't)

It fits if you started investing early, you're burned out on high-stress work, and you'd happily take a lower-paying job if it didn't blow up your retirement. Coast FIRE gives you permission to do exactly that.

It's riskier if you're relying on aggressive return assumptions, you have no buffer for a bad decade of markets, or your "coasting" job wouldn't actually cover your real expenses. Coasting only works if the lower-stress job genuinely pays the bills without dipping into the invested pile.