Coast FIRE at 40
Coast FIRE number at 40
$276,374
On $5,000 a month of spending, invested once and never added to, compounding at 7 percent real for 25 years until 65. That is 18 percent of the $1,500,000 you are aiming at.
By 40 the arithmetic has shifted. You have twenty five years of compounding left rather than forty, and the coast number at $5,000 a month of spending is around $276,000.
That is still less than a fifth of the $1.5 million you are aiming at, which is the part that surprises people.
Coast FIRE at 40 by monthly spending
| Monthly spending | FIRE number | Coast FIRE at 40 |
|---|---|---|
| $3,000 | $900,000 | $165,824 |
| $4,000 | $1,200,000 | $221,099 |
| $5,000 | $1,500,000 | $276,374 |
| $6,000 | $1,800,000 | $331,649 |
| $8,000 | $2,400,000 | $442,198 |
Twenty five years is still a lot of compounding
There is a version of the FIRE conversation that treats 40 as late. It is not. Money invested at 40 still multiplies more than five times by 65, so a bit over a quarter of a million dollars covers a $1.5 million target on its own.
What does change at 40 is the cost of being wrong. At 25 a bad decade of returns can be absorbed by the thirty years that follow. At 40 there is less room, which is why the sensitivity table matters more here. If real returns come in at 5 percent rather than 7, the coast number at 40 rises from about $276,000 to about $443,000. That is not a rounding error, it is a different plan.
If returns disappoint
The return assumption moves this number more than anything else you can control. At $5,000 a month of spending, here is the same calculation at 40 across a realistic range.
| Real return | Coast FIRE at 40 |
|---|---|
| 5 percent | $442,954 |
| 6 percent | $349,498 |
| 7 percent | $276,374 |
| 8 percent | $219,027 |
Run it on your own numbers
Your spending, your retirement age, your return assumption, and what you already have invested.
Open the Coast FIRE calculatorCommon questions
Is 40 too late to start?
No, but the honest framing is that at 40 contributions do more work than compounding for the first stretch, which is the reverse of the position at 25. Someone starting from zero at 40 is not coasting anywhere and should focus on savings rate rather than on this number.
Should I include my 401k employer match?
Include the balance, yes. But if you stop contributing you usually stop receiving the match, and for many people the match is worth several percent of salary a year. Coasting therefore costs more than it appears, because you give up free money as well as your own contributions.
Coast FIRE at other ages
- Age 25 · $100,171
- Age 30 · $140,494
- Age 35 · $197,051
- Age 45 · $387,629
- Age 50 · $543,669
- Age 55 · $762,524
Figures assume a 4 percent withdrawal rate, 7 percent real returns and retirement at 65, with spending expressed in today's money. This is general information, not financial advice.