Coast FIRE is the moment you can stop saving for retirement entirely — and still arrive at your full retirement number on time, purely from the growth of what you already have invested. From that point you only need to earn enough to cover today's living costs. Your retirement is, in effect, on autopilot.
Check whether you're already coasting
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How Coast FIRE differs from FIRE
Regular FIRE means you have enough to stop working. Coast FIRE is an earlier, gentler milestone: you have enough invested that you can stop adding to retirement, because compounding alone will carry your existing balance to the target by your chosen retirement age. You still work — but only to pay for your current life, not to fund your future.
The math behind it
Your Coast FIRE number is whatever amount, left untouched and compounding at your expected return, grows into your full FIRE number by retirement age. The earlier in life you reach it, the smaller it is, because compounding has more years to work.
Example. Say your full FIRE number is $1,000,000, you are 30, you plan to retire at 65, and you expect a 5% real return. That is 35 years of growth, so your coast number today is:
| Figure | Value |
|---|---|
| Full FIRE number | $1,000,000 |
| Years of growth (30 → 65) | 35 |
| Coast number needed at 30 | ~$181,000 |
In other words, about $181,000 invested by age 30 — with no further retirement saving — would grow to roughly $1,000,000 by 65 at a 5% real return. The Coast FIRE Calculator works out your exact number for any age, target and return.
Why it's such a powerful milestone
Coast FIRE buys freedom long before full independence does. Once you hit it, you can:
- Downshift to lower-paid but more meaningful work, since you only need to cover living costs.
- Take a career break or go part-time without derailing retirement.
- Stop the pressure of maximizing retirement contributions — the future is already funded.
It reframes financial independence as a spectrum rather than a single finish line, and the first big step on it arrives surprisingly early for those who invest young.
Check whether you're already coasting
Free and private — see the amount you need invested today to coast to retirement.
How to find your coast number
- 1. Estimate your FIRE number — your annual retirement spending times 25.
- 2. Choose a retirement age and count the years of growth ahead.
- 3. Pick an expected real return (after inflation), commonly somewhere around 4–6%.
- 4. Divide the FIRE number by growth over those years — or let the calculator do it.
- 5. Compare it to what you already have invested to see if you are coasting yet.
The bottom line
Coast FIRE is the point where your invested savings will grow into your retirement number on their own, so you can stop saving for the future and just fund the present. It is the earliest, most freeing milestone on the path to independence — and for young investors, it can arrive far sooner than full FIRE.
Check whether you're already coasting
Free and private — see the amount you need invested today to coast to retirement.
Frequently asked questions
How is Coast FIRE different from FIRE?
Full FIRE means your portfolio can cover your expenses and you can stop working. Coast FIRE means you can stop saving for retirement — your existing investments will grow into the full number on their own — but you still work to cover current living costs until retirement.
Why does the coast number rise as I get older?
Fewer years until retirement means less time for compounding, so you need more invested today to reach the same goal. A 25-year-old needs far less than a 50-year-old to coast to the same target.
Do I have to stop saving entirely once I coast?
Not necessarily. In theory you can stop saving for retirement, but many people keep investing for a margin of safety, earlier independence, or bigger goals. Coasting is permission to ease off, not a rule that you must stop.
What return should I use for Coast FIRE?
A real, after-inflation return keeps the target in today's money — commonly somewhere around 4% to 6% for a diversified portfolio. Use a lower figure for a more cautious estimate.