What Is Coast FIRE?
Coast FIRE is the moment you have invested enough that compound growth alone will carry you to your retirement target — without saving another dollar. You still work to cover today's bills, but retirement is already funded. Aiming for a $1,200,000 portfolio at 65 with a 7 percent return, a 30-year-old reaches Coast FIRE at about $104,292. That balance, left alone for 35 years, does the rest. It is a far earlier milestone than full FIRE, and for many people a far more reachable one.
The short answer
You have hit Coast FIRE when your invested balance, left completely alone, will grow into your retirement target by the age you plan to retire. No further contributions required — compounding finishes the job.
You do still need an income, because your day-to-day expenses are not covered by the portfolio yet. What changes is that you no longer have to save for retirement. Every dollar you earn from that point can go to living, or to freedom: a shorter week, a career change, a lower-paid job you actually like.
Run your own numbers: the FIRE calculator works out your target, and the future value calculator shows what a balance grows to if you leave it untouched.
Coast FIRE vs regular FIRE
They sound similar and are often confused, but they answer different questions:
| Coast FIRE | Regular FIRE | |
|---|---|---|
| What is funded | Retirement at your normal retirement age | Your living expenses, starting now |
| Do you still work? | Yes — to pay current bills | Optional |
| Do you still save for retirement? | No | No |
| Portfolio needed at 30 (for a $1,200,000 goal) | About $104,292 | $1,200,000 |
The difference in what you need is enormous, and that is the appeal. Full FIRE demands roughly 25 times your annual expenses in hand today — see how to calculate your FIRE number. Coast FIRE asks only for the seed that grows into it.
A worked example
Take someone aged 30 who wants a $1,200,000 portfolio by 65 — the target for roughly $48,000 a year of spending under the 4 percent rule. They assume a 7 percent annual return, compounded monthly, and they have 35 years of growth ahead.
Working backwards from the target, they need about $104,292 invested today. Leave that balance alone and it compounds for 35 years into the full $1,200,000, with no further contributions at any point.
| Element | Value |
|---|---|
| Retirement target at 65 | $1,200,000 |
| Years of growth (age 30 → 65) | 35 |
| Assumed return | 7% a year, compounded monthly |
| Coast FIRE number at 30 | $104,292 |
| Further contributions needed | None |
Someone at 30 with $150,000 already invested is comfortably past their Coast FIRE point — that balance alone would grow to about $1,725,923 by 65. They could stop retirement saving entirely today and still land well above target.
Coast FIRE number by age
The later you start, the less time compounding has, so the number climbs steeply. Here is what you need invested at each age to coast to $1,200,000 by 65 at a 7 percent return:
| Your age | Years of growth | Coast FIRE number |
|---|---|---|
| 25 | 40 | $73,568 |
| 30 | 35 | $104,292 |
| 35 | 30 | $147,847 |
| 40 | 25 | $209,592 |
| 45 | 20 | $297,122 |
| 50 | 15 | $421,208 |
Waiting from 25 to 45 nearly quadruples what you need — from about $73,568 to about $297,122 — for exactly the same retirement. This is the clearest argument for investing early that the FIRE framework produces.
The math behind it
Coast FIRE is present value: the target discounted back to today.
Here r is the annual return as a decimal, t is the years until retirement, and 12t is the number of months. For the $1,200,000 target at 7 percent with 35 years to run, that is 1,200,000 ÷ (1 + 0.07/12)420 = about $104,292. It is the same compounding math used everywhere else on this site, just run in reverse — see the future value of money formula for the forward version.
What it does and does not buy you
Coast FIRE is a genuine milestone, but it is easy to overstate:
- It does mean you can stop saving for retirement and redirect that money to living now, or to lowering your working hours.
- It does not mean you can retire. Your expenses today are still unfunded — that is what full FIRE is for.
- It leans hard on the return assumption. Coasting relies entirely on decades of compounding, so a lower-than-expected return leaves you short with less time to fix it.
- It is reversible. Many people who reach Coast FIRE keep contributing anyway, treating it as a safety margin rather than a finish line.
Assumptions
- Monthly compounding at 7 percent. Growth figures use a 7 percent annual return compounded monthly, matching this site's calculators.
- Retirement at 65. The tables assume a traditional retirement age; retiring earlier shortens the growth runway and raises the number.
- No withdrawals or further contributions. The balance is left completely untouched, which is the whole premise of coasting.
- The target uses the annual 4% convention. The $1,200,000 goal comes from $48,000 of annual spending under the 25x rule, which is defined yearly.
Frequently asked questions
The bottom line
Coast FIRE is the point where compounding takes over. Get a modest amount invested early — about $104,292 by 30 for a $1,200,000 goal — and retirement funds itself while you get on with your life. It is not early retirement, but it is the milestone that makes early retirement feel possible.
Work out your own target with the FIRE calculator, project a balance forward with the future value calculator, or plan a traditional path with the retirement calculator.
Disclaimer: This page is for general educational purposes only and is not financial advice. The examples use assumed rates of return to illustrate how Coast FIRE works; they are projections, not guarantees, and actual results vary with markets, inflation, taxes and fees. Consider speaking with a qualified financial professional before making decisions about your own money.