What is the Coast FIRE number at age 40?
Under a 7% nominal return, 2.5% inflation, $40,000 of annual expenses, a 4% withdrawal rate and retirement at 65, a 40-year-old's Coast FIRE number is approximately $342,000 — higher than at 30 or 35 because fewer years remain for compounding to do the work.
Run it with your own numbers
The Coast FIRE Calculator below is loaded with this scenario's assumptions. Change any input and the answer updates instantly.
Coast FIRE number
$341,588
Enough to coast from today.
Your progress
14.6%
Toward the Coast FIRE number.
Assumptions behind this number
- 7% nominal expected return; 2.5% inflation → ~4.4% real growth.
- Monthly compounding; figures in today's purchasing power.
- Retirement age 65; annual expenses $40,000; 4% withdrawal rate → a $1,000,000 FI number in today's dollars.
- No taxes, fees, or contribution changes modelled.
- The starting balance is illustrative and only affects the "are you coasting yet?" progress; the Coast FIRE number depends only on age, retirement age, expenses, withdrawal rate and return. Change any value above.
Why the number comes out this way
At 40 there are 25 years to a 65 retirement — still a long runway, but shorter than the 30-plus years a younger starter has. Because the required amount is the target discounted over fewer years, the number climbs to ~$342,000: roughly $66,000 more than at 35 and $119,000 more than at 30, for the exact same $1,000,000 goal.
Even so, 25 years of ~4.4% real growth still roughly triples a dollar, so compounding is carrying most of the load — a mid-career starter is far from "too late," they simply need a larger seed to buy the same finish.
The step-up between the by-age numbers is the clearest illustration of the time-value lever: the size of the gap is the cost of the years already spent. As always, the target is in today's dollars because growth is modelled at the real rate.
Keep exploring
Related scenarios and the concepts behind them.
Frequently asked questions
Why is the Coast FIRE number higher at 40?
Fewer years to retirement mean compounding has less time, so a larger amount today is needed to reach the same target under these assumptions.
Is 40 too late for Coast FIRE?
Under these assumptions 25 years of real growth still roughly triples a starting balance, so a larger seed reaches the same goal — the calculator lets you test your own timeline.
How much more is needed than at 35?
About $66,000 more (≈$342,000 vs ≈$276,000), reflecting the five fewer years of compounding.
Can I lower the number by planning to retire later?
Yes — a later retirement age adds compounding years and lowers the required amount; change the retirement age to see the effect.
Does this account for taxes or fees?
No — it is a simplified educational projection under stated assumptions; taxes and fees would change real-world outcomes.
Educational use only
Educational purposes only. Calculator results are estimates based on assumptions and user inputs. They are not financial, investment, legal, or tax advice. Investing involves risk, including possible loss of principal. Past performance does not guarantee future results.