Coast FIRE Explained
Coast FIRE is the point at which your existing investments, left to compound without any further contributions, will grow to your full FIRE number by your target retirement age. Once you reach Coast FIRE, you only need to earn enough to cover current expenses — retirement savings are done.
How to Calculate Your Coast FIRE Number
The Coast FIRE formula works backwards from your target retirement portfolio to a present value using expected compound growth:
At $462,000 in investments at age 35, you can stop all retirement savings. The money compounds to $2M by 65 on its own. You still need to earn enough to live — but you're free from the pressure of saving for the future.
Coast FIRE in Australia includes super. Your superannuation counts towards your Coast FIRE number, but with a critical caveat: super is locked until preservation age (60). If you want to retire before 60, you need a separate accessible portfolio to bridge the gap. Run both numbers separately — Coast FIRE for accessible investments and Coast FIRE for your full picture including super.
Coast FIRE vs Full FIRE
The difference is the pressure on your present. Full FIRE requires building a portfolio large enough to live off for the long term — right now. Coast FIRE only requires building a portfolio large enough that time can do the rest. Coast FIRE is typically reachable 5–12 years before full FIRE.
| Full FIRE | Coast FIRE | |
|---|---|---|
| Portfolio needed now | Full FIRE number (~25× expenses) | Fraction of FIRE number |
| Can you stop saving? | Yes — and stop working | Yes — but still need income for expenses |
| Flexibility | Maximum | High — any income-covering job works |
| Time to reach (typical) | 15–25 years | 8–15 years |
| Risk | Sequence of returns at retirement | Lower — long compounding runway |
What Changes After Coast FIRE?
Once you hit Coast FIRE, the psychological shift is significant. You're no longer saving for retirement — you're just covering living expenses. This opens options that full FIRE doesn't:
- Work you actually want to do. Barista FIRE, creative work, part-time roles — any job that covers expenses lets you coast for as long as you need to.
- Lower income requirements. You only need to cover current costs, not save 20–40% of income. A $60k lifestyle only needs ~$75k gross income (once tax is factored in).
- Taking career breaks. A 6-month sabbatical doesn't derail your retirement timeline — the compound growth is already locked in.
- Location flexibility. Lower income requirements mean you can take lower-paying jobs in preferred locations.
Coast FIRE Numbers for Australians
The following shows the Coast FIRE portfolio required at different ages to reach $2M by age 65, assuming 5% real annual returns (roughly 7.5% nominal minus 2.5% inflation):
| Your age now | Years to 65 | Coast FIRE number |
|---|---|---|
| 25 | 40 | $284,000 |
| 30 | 35 | $362,000 |
| 35 | 30 | $462,000 |
| 40 | 25 | $590,000 |
| 45 | 20 | $754,000 |
| 50 | 15 | $962,000 |
Target: $2M at 65 (≈ $80k/year at 4% SWR). 5% real return assumed. Includes all investments — super plus accessible portfolio.
The Risk: Contribution Rate After Coast FIRE
Coast FIRE assumes you stop contributing and let compounding do the work. The risk is that extended periods of low or no contributions at younger ages dramatically reduce where you land. A 5-year return drought in your 30s, combined with having already stopped contributing, can push your real retirement date out significantly.
The mitigation: if the market cooperates, you reach 65 ahead of schedule. If it doesn't, you had the flexibility of coasting and can reassess. Coast FIRE is directionally correct even when markets don't cooperate — it's just no longer a guarantee.
Model your Coast FIRE date
The FIRE calculator models both your accumulation phase and the point at which compounding takes over. Enter your current balances, savings rate, and target retirement age.
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