Coast FIRE is the moment your invested savings are big enough to grow into a full retirement on their own — so you can stop saving for retirement entirely and only cover today's bills. If your goal is a $1,250,000 portfolio and you're 30, you need about $329,000 invested today. After that, compounding does the rest while you coast.
How Coast FIRE works
Full FIRE means you have the whole portfolio and never have to work again. Coast FIRE is an earlier milestone: your existing investments, left untouched, will compound to your full FIRE number by your target retirement age — no new contributions required. You still work to pay rent, food, and healthcare, but every retirement-savings dollar is already in the market. Your starting target comes from your FIRE number, which is based on retirement spending and a sustainable withdrawal rate. If you want to see where Coast sits relative to the two other common paths, read Regular FIRE vs Coast FIRE vs Barista FIRE.
The earlier you hit it, the smaller the lump sum, because your money has more years to compound. Here is the Coast FIRE number for a $1,250,000 goal (a $50,000-a-year retirement at the 4% rule), assuming a 7% return and 3% inflation — about a 3.9% real return — and retirement at 65:
| Your age now | Years to 65 | Coast FIRE number (today's dollars) |
|---|---|---|
| 25 | 40 | $272,000 |
| 30 | 35 | $329,000 |
| 35 | 30 | $399,000 |
| 40 | 25 | $482,000 |
Notice the pattern: at 25 you need barely a fifth of the final number invested; at 40 you need almost twice as much. Time, not contribution size, is the lever.
Coast FIRE number by age
The curve gets steeper as retirement approaches because each delayed year removes a year of compounding. Under the same assumptions, waiting from age 30 to 40 raises the amount needed today by about $153,000.
The Coast FIRE formula
The real return is your nominal return minus inflation. At a 7% return and 3% inflation, that is about 3.9%. For a 30-year-old with a $1,250,000 goal retiring at 65 (35 years away): $1,250,000 ÷ (1.039)35 ≈ $1,250,000 ÷ 3.79 ≈ $329,000. We discount with the real return so the answer is in today's dollars, directly comparable to your current balance.
This is the same present-value math behind a compound interest calculator. Use conservative assumptions and test several return rates instead of treating one projection as a promise.
Am I Coast FIRE yet?
You have reached Coast FIRE when your current invested balance is at least as large as your Coast FIRE number. Compare invested retirement assets — not your home equity or emergency fund — with the threshold.
| Age 35 example | Current portfolio | Coast FIRE number | Result |
|---|---|---|---|
| Above the threshold | $450,000 | $399,000 | Already Coast FIRE |
| Below the threshold | $250,000 | $399,000 | Keep contributing |
In the first example, $450,000 left invested from age 35 to 65 could grow beyond the $1.25 million target in today's dollars without another contribution. In the second, the portfolio needs more contributions, more time, a lower spending target, or some combination of the three.
Calculate your Coast FIRE number
Your real answer depends on your age, current portfolio, retirement age, spending target, withdrawal rate, investment return, and inflation. The calculator estimates:
- Your Coast FIRE target in today's dollars
- Whether your current invested balance has reached it
- Your projected FIRE age and future portfolio value
- How changing contributions or assumptions affects the timeline
Coast FIRE vs. Traditional FIRE vs. Barista FIRE
Coast FIRE changes how much you need to save, not whether you need income today. That makes it different from both full FIRE and Barista FIRE. For the head-to-head, see Coast FIRE vs Barista FIRE, or step back for the full map of FIRE types.
| Type | Need to keep saving? | Need to keep working? | Portfolio role |
|---|---|---|---|
| Coast FIRE | No, for retirement | Yes, to cover current expenses | Left invested to grow |
| Barista FIRE | Possibly | Part-time or lower-income work | Covers the spending gap |
| Traditional FIRE | No | No | Funds current living expenses |
Why Coast FIRE matters
It buys freedom before full FIRE. Once you coast, you can switch to a lower-stress or part-time job, take a sabbatical, or change careers, knowing your retirement is already funded. It is also the milestone that makes a Slow FIRE plan work — the point where a lower savings rate can finally ease off. A 28-year-old who front-loads $330,000 can stop retirement saving for the next 37 years and still land around $1.25M in today's dollars at 65.
Starting age dominates. Coasting at 25 takes $272,000; waiting until 40 takes $482,000 for the same goal — a $210,000 penalty for 15 years of delay. The first dollars you invest are the most powerful because they compound the longest.
How to reach Coast FIRE in the US
- Use tax-advantaged accounts. Compare a 401(k) and Roth IRA for FIRE based on your match, taxes, and access needs.
- Capture your full 401(k) match. An employer match is an instant return that accelerates how fast you hit the coast number.
- Use low-cost index funds. A 1% fee compounds against you exactly the way returns compound for you, and it quietly raises the balance you need to coast.
Common Coast FIRE mistakes
1. Touching the money. Coasting only works if you leave the portfolio alone. Pull $50,000 out at 35 and you don't just lose $50,000 — you lose what it would have compounded to by 65.
2. Ignoring healthcare and taxes. Your coast number is built on your real spending. Healthcare can be one of the largest expenses before Medicare eligibility at age 65, and costs vary widely by location, household, plan, and ACA subsidy eligibility. Model it explicitly using a pre-Medicare healthcare plan.
3. Treating the 4% rule as guaranteed. Withdrawal rates depend on retirement length, portfolio mix, fees, and market sequence. Read the 4% rule assumptions and test a more conservative target too.
Coast FIRE FAQ
What is a good Coast FIRE number?
A good Coast FIRE number is one built from your own retirement spending, retirement age, and conservative real-return assumption. There is no universal dollar amount: an earlier age and lower spending target reduce the amount needed today.
Can I stop working after reaching Coast FIRE?
Not usually. Reaching Coast FIRE means you may stop contributing toward retirement, but you still need income for current living expenses. Stopping work entirely requires full FIRE or another reliable source of income.
Does Coast FIRE assume no future contributions?
Yes. The standard calculation assumes your current portfolio receives no new contributions and no withdrawals until retirement. Continuing to contribute creates a margin of safety or may move your full FIRE date earlier.
What return rate should I use for Coast FIRE?
Use an inflation-adjusted, after-fee return consistent with your portfolio. Testing several rates — including a conservative case — is more useful than relying on a single optimistic forecast.
Is Coast FIRE realistic with index funds?
Broad, low-cost index funds can fit a Coast FIRE plan, but no investment return is guaranteed. Your asset allocation, fees, taxes, time horizon, and ability to leave the portfolio untouched all affect the outcome.
What to read next
All projections assume a fixed annual return and inflation rate and no withdrawals. Past market returns do not guarantee future results. This article is educational and does not constitute financial advice.