Coast FIRE by Age: How Much You Need at 25, 30, 35, 40 and 45
Coast FIRE numbers by age: see roughly how much you need invested at 25, 30, 35, 40 and 45 to coast to retirement — and why starting earlier means a far smaller number.
Coast FIRE by Age: How Much You Need at Each Age
One of the most striking things about Coast FIRE is how much your age changes the answer. Because the whole idea relies on compound growth doing the heavy lifting between now and retirement, the more years you have, the less you need invested today.
This guide gives rough by-age benchmarks and explains what moves them.
The assumptions behind the benchmarks
These numbers assume:
- Retirement age: 65
- Annual retirement spending: $40,000
- Safe withdrawal rate: 4% → a full FIRE number of $1,000,000
- Real (after-inflation) return: ~5%
The Coast FIRE number is the full FIRE number discounted back to your current age:
Coast number = FIRE number ÷ (1 + real return) ^ (years to retirement)
Coast FIRE number by age
| Current age | Years to 65 | Approx. Coast FIRE number |
|---|---|---|
| 25 | 40 | ~$142,000 |
| 30 | 35 | ~$181,000 |
| 35 | 30 | ~$231,000 |
| 40 | 25 | ~$295,000 |
| 45 | 20 | ~$377,000 |
Notice the pattern: a 25-year-old needs less than half of what a 45-year-old needs to reach the same retirement — for an identical lifestyle. That's not a quirk; it's compounding rewarding time in the market.
These are illustrative. Your real number depends on your spending, target retirement age, and return assumptions. Calculate your exact number →
Why the number climbs so fast with age
Every year you wait is one fewer year of compounding. At a 5% real return, money roughly doubles every ~14 years. So a dollar invested at 25 can double almost three times before 65; a dollar invested at 45 barely doubles once. The earlier dollars simply do more work.
This is also why "I'll start later when I earn more" is so costly — the later start raises your coast number much faster than a raise typically raises your savings.
What if you're starting later?
If you're 40+ and the number looks daunting, you have levers:
- Retire a little later (67 instead of 65) — even two more years of compounding lowers the number meaningfully.
- Trim retirement spending — the FIRE number scales directly with spending.
- Factor in Social Security or a pension, which reduces the amount your own portfolio must cover. See the with Social Security calculator.
The takeaway
Coast FIRE rewards starting early more than almost any other financial milestone. If you're young, a surprisingly modest amount invested now can put retirement on autopilot. If you're older, the number is bigger but still far smaller than full FIRE — and the levers above keep it reachable.
Find your Coast FIRE number for your exact age → or learn what Coast FIRE is.
This article is for educational purposes only and is not financial advice. Figures are illustrative and depend on assumptions that may not match your situation.