fire ~3 min read
Coast FIRE number by age (with table)
Your Coast FIRE number is your full FIRE number discounted back to today by compound growth. A table of Coast FIRE targets at ages 25–45 for a $1M goal, the formula, and a live calculator.
Your Coast FIRE number is your full FIRE number discounted back to today by compound growth — so it’s smaller the younger you are. For a $1,000,000 goal at age 65 and a 7% real return:
| Age now | Years to 65 | Coast FIRE number |
|---|---|---|
| 25 | 40 | ~$66,800 |
| 30 | 35 | ~$93,700 |
| 35 | 30 | ~$131,000 |
| 40 | 25 | ~$184,000 |
| 45 | 20 | ~$258,000 |
Hit your number and growth alone is expected to carry you to $1M by 65 — even if you never contribute another dollar.
Coast FIRE is the most useful early waypoint on the path to financial independence. It doesn’t mean you can stop working — it means you can stop saving, because compound growth will finish the job. This page shows the number at each age and where it comes from.
The Coast FIRE formula
Coast FIRE Number = Full FIRE Number ÷ (1 + r)^nwhere r is your real (after-inflation) return and n is the number of years until your target retirement age. It’s just the FIRE number run backwards through compound growth: instead of asking “how big must my portfolio be at 65?”, it asks “how much must I have today so it grows to that by 65 on its own?”
Coast FIRE number by age (for a $1M goal)
Assuming a $1,000,000 full FIRE number (a $40,000/year lifestyle at 4%), retirement at 65, and a 7% real return:
| Age now | Years of growth | Growth factor (1.07ⁿ) | Coast FIRE number |
|---|---|---|---|
| 25 | 40 | 14.97× | ~$66,800 |
| 30 | 35 | 10.68× | ~$93,700 |
| 35 | 30 | 7.61× | ~$131,000 |
| 40 | 25 | 5.43× | ~$184,000 |
| 45 | 20 | 3.87× | ~$258,000 |
The pattern is the whole point: a 25-year-old needs under $67k invested to coast; a 45-year-old needs nearly four times that for the identical end goal. Every year you start earlier dramatically lowers the bar, because the money compounds longer.
Two things that change the number
Your real return assumption. The table uses 7% real. Drop it to 5% and every number rises sharply — at age 30, the $93,700 becomes about $181,000. Use real (inflation-adjusted) returns with today’s-dollar expenses; mixing nominal returns with real spending overstates your trajectory badly.
Your spending. The table assumes a $1M goal ($40k/year). If you’ll spend $60k, your full FIRE number is $1.5M and every figure above scales up by 1.5×. Scale to your own goal first, then discount by age.
Run your own age and goal
$1.25M
projected at age 61
Your money compounds to $1.25M by age 61. That's 4 years ahead of your retirement target.
- FIRE number
- $1.25Mannual ÷ SWR
- Coast target
- $134Kat age 32
- Projected at retirement
- $1.68Mcompounding only
- Real return
- 7.0%inflation-adjusted
Hitting Coast FIRE doesn’t force any decision — it just changes the meaning of your paycheck from “necessary to retire on time” to “necessary only to cover today’s expenses.” That’s the optionality worth knowing the number for.
Go deeper:
- How to Calculate Your FIRE Number — the full framework, including the Coast FIRE section.
- The FIRE formula — the core equation and each variant.
- Compound interest: the engine behind it — why starting earlier matters so much.
Try the Coast FIRE Calculator with your own numbers — it runs entirely in your browser.
Educational content, not financial advice. Figures assume a 7% real return and a 4% withdrawal rate; your results depend on your inputs and future returns may differ.