At $40,000 of annual spending, a 4% withdrawal rate and 5% real growth, the FI number is $1,000,000. The Coast FIRE number is what that target is worth today at each age: $181,290 at 30, $376,889 at 45 and $613,913 at 55. Between 30 and 45 the number roughly doubles, because fifteen fewer years of compounding has to be paid for with a larger balance today.
Spending $40,000 a year at a 4% withdrawal rate needs $1,000,000 invested. The Coast FIRE number for age 30 is $181,290, so you still need $181,290.
Spending $40,000 a year at a 4% withdrawal rate needs $1,000,000 invested. Your Coast FIRE number for age 30 is $181,290, and your portfolio is already $0 past it.
Every number below comes from the same four assumptions: $40,000 of annual spending, a 4% withdrawal rate, 5% real growth after inflation, and retirement at 65. The first two fix the FI number at $1,000,000; the third decides how much that target is worth today at each age.
Coast FIRE number = $1,000,000 ÷ 1.05(65 − age)
| Age today | Years to 65 | Coast FIRE number |
|---|---|---|
| 25 | 40 | $142,046 |
| 30 | 35 | $181,290 |
| 35 | 30 | $231,377 |
| 40 | 25 | $295,303 |
| 45 | 20 | $376,889 |
| 50 | 15 | $481,017 |
| 55 | 10 | $613,913 |
| 60 | 5 | $783,526 |
| 65 | 0 | $1,000,000 |
Read a row as the balance you need to be holding today, not the amount you will have contributed by then. At 30 the table shows $181,290 and at 55 it shows $613,913. Both are the same $1,000,000 target, discounted over a different number of compounding years.
The climb is exponential, not linear. Each extra year multiplies the previous balance rather than adding to it, so the divisor grows faster the further out you look. Moving from 55 to 45 cuts the required balance from $613,913 to $376,889, a saving of $237,024 for ten extra years of growth. The steep part of the curve sits at older ages, where few years remain and the discounting is weak. That is also where people most need the number to be small, which is why starting early is worth more than optimising returns by a fraction of a percent.
The table is deliberately fixed so that every row can be checked by hand. If your spending is not $40,000, scale the whole column: $30,000 of spending means 75% of each figure, and $60,000 means double. If your return or retirement age differs, scaling will not work, because those inputs change the exponent rather than the target. Use the calculator above instead, or the coast fi calculator and the financial independence calculator, which take your own inputs directly.
With $40,000 of spending, a 4% withdrawal rate and 5% real growth to age 65, the Coast FIRE number at 30 is $181,290. It is the amount that grows to $1,000,000 over 35 years without further contributions.
Because compounding has less time to run. The divisor shrinks every year, and because it is exponential the effect accelerates: the difference between 30 and 40 is about $114,000, while the difference between 55 and 65 is about $386,000.
Yes. Every figure assumes the balance is left alone from that age, with contributions stopping immediately. If you plan to keep saving, the number you need today is lower, and the calculator on this page lets you add a yearly contribution to see how much lower.
The table fixes retirement at 65. Retiring earlier raises the Coast FIRE number at every age, because the portfolio has fewer years to grow and the withdrawal period is longer. Recalculate with your own retirement age rather than scaling the table.
Yes, but not with this table, which is fixed at 4% and 5%. Changing either input moves both columns: a lower return raises every number, and a lower withdrawal rate raises the $1,000,000 target that everything is discounted from. Use the calculator above for the general version.