Coast FIRE Explained: The Art of Doing Enough
Coast FIRE is one of the most underrated FIRE milestones — the point where your investments will grow to your FIRE number on their own, even if you never contribute another dollar. Here's how it works.
Most FIRE conversations focus on the finish line: the day you hit your full FIRE number and walk away from work forever. But there’s a milestone worth celebrating long before that — Coast FIRE.
Coast FIRE is the point where you can stop contributing to your investments entirely and your existing portfolio will still compound to your full FIRE number by traditional retirement age. You’ve done enough investing. Now you just coast.
The Math Behind Coasting
Your Coast FIRE number is your FIRE number discounted back to today:
Coast Number = FIRE Number ÷ (1 + r)^years
If your FIRE number is $1,250,000, you expect 7% real returns, and you have 25 years until you’d want to retire:
$1,250,000 ÷ (1.07)^25 = $1,250,000 ÷ 5.43 ≈ $230,000
At $230,000 invested today, compounding alone gets you to $1.25M in 25 years — even if you never invest another dollar.
Try the Coast FIRE Calculator to find your own Coast number instantly.
Why Coast FIRE Changes Everything
The moment you hit your Coast number, the financial pressure changes fundamentally. You no longer need a high-savings-rate job. You just need to cover your current expenses — which is a much easier bar to clear.
This opens doors that full FIRE doesn’t require you to wait for:
- Career change: Take the lower-paying job you actually love
- Go part-time: Work 20 hours instead of 50
- Freelance / consult: Build the business you wanted, without the income pressure
- Move cheaper: Geographic arbitrage becomes much easier when you just need to cover expenses
Coast FIRE is sometimes called the “permission slip” milestone — it gives you permission to optimize for life satisfaction rather than maximum savings rate.
Coast FIRE vs. Barista FIRE
These two are often confused:
| Coast FIRE | Barista FIRE | |
|---|---|---|
| Investments needed | Enough to compound to FIRE number | Smaller portfolio |
| Income needed | Just cover current expenses | Covers expenses + benefits |
| Investing | No more contributions required | May still add small amounts |
| Goal | Let compounding do the work | Part-time work + partial portfolio |
Barista FIRE is about the income strategy. Coast FIRE is about the portfolio milestone. You can be in Barista FIRE without being at Coast FIRE, and vice versa.
The Assumptions That Matter
Two variables drive your Coast number more than anything else:
Expected real return rate: Using 7% (a common inflation-adjusted estimate for a diversified stock portfolio) gives very different results from using 5%. A lower assumed return means a higher Coast number — be conservative if you want a margin of safety.
Years until retirement: The earlier you’re coasting, the more years compounding has to work. Someone with 30 years left needs a much smaller Coast number than someone with 15.
Our calculator lets you adjust both — and shows a “Coasting Age Explorer” table that finds the earliest age at which you’d hit your Coast number given your current trajectory.
Limitations to Know
Coast FIRE doesn’t mean you’re financially independent today. You still need income to cover current expenses. The win is that you’ve removed the pressure to aggressively invest — not the pressure to earn.
Markets don’t compound smoothly. The math assumes steady returns, but real returns are lumpy. A bad sequence of returns in the years after you “hit” Coast can delay the outcome. Many people build a 10–20% buffer into their Coast number as insurance.
Inflation matters. We recommend using real (inflation-adjusted) returns in Coast FIRE calculations, which our calculator does by default.
Is Coast FIRE Right for You?
If you’re the kind of person who could happily cover expenses with meaningful-but-less-stressful work — and the financial independence endgame feels like it’s 20+ years away — Coast FIRE is a compelling intermediate goal to optimize for.
It’s the milestone that says: you’ve done the hard work of getting the money started. Now time does the rest.
Find your personal Coast FIRE number with the Coast FIRE Calculator.