$2,500 a month for 15 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $611,643 | $161,643 | $392,590 |
| 5% | $662,061 | $212,061 | $424,952 |
| 6% | $717,280 | $267,280 | $460,395 |
| 7% | $777,762 | $327,762 | $499,216 |
| 8% | $844,016 | $394,016 | $541,742 |
| 10% | $996,110 | $546,110 | $639,365 |
Year by year at 7%
| Year | Put in so far | Balance | In today’s dollars |
|---|---|---|---|
| 1 | $30,000 | $30,951 | $30,049 |
| 2 | $60,000 | $64,068 | $60,390 |
| 3 | $90,000 | $99,504 | $91,060 |
| 4 | $120,000 | $137,420 | $122,095 |
| 5 | $150,000 | $177,990 | $153,535 |
| 6 | $180,000 | $221,400 | $185,419 |
| 7 | $210,000 | $267,848 | $217,785 |
| 8 | $240,000 | $317,549 | $250,676 |
| 9 | $270,000 | $370,728 | $284,132 |
| 10 | $300,000 | $427,629 | $318,196 |
| 11 | $330,000 | $488,514 | $352,913 |
| 12 | $360,000 | $553,661 | $388,327 |
| 13 | $390,000 | $623,368 | $424,483 |
| 14 | $420,000 | $697,954 | $461,430 |
| 15 | $450,000 | $777,762 | $499,216 |
The range in 1,000 simulated markets
A 7% average does not arrive as 7% every year. In 1,000 simulated sequences of returns averaging 7% with 12% volatility, this is where $2,500 a month ended up: 1 in 10 markets finished below the first figure, half below the middle one, and 1 in 10 above the last.
| After | Weak (1 in 10 lower) | Middle | Strong (1 in 10 higher) |
|---|---|---|---|
| 8 years | $243,331 | $312,588 | $394,239 |
| 15 years | $516,598 | $743,199 | $1,056,729 |
The middle of the simulation sits below the steady 7% figure of $777,762 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $777,762 would pay in retirement
At a 4% first-year withdrawal, $777,762 pays about $31,110 a year, $2,593 a month, before tax; in today’s dollars that is about $19,969 a year. How long a balance near it lasts at each withdrawal: how long $800,000 lasts. To stop saving early and let growth do the rest, see Coast FIRE numbers by age.
$30,000 a year is more than the 2026 401(k) limit of $24,500, so part of it would go to a taxable account or a spouse’s plan. See contribution limits, the 401(k) calculator and the Roth IRA calculator.
$2,500 a month for other terms
| Years | Balance | In today’s dollars |
|---|---|---|
| $2,500 a month for 5 years | $177,990 | $153,535 |
| $2,500 a month for 10 years | $427,629 | $318,196 |
| 15 years | $777,762 | $499,216 |
| $2,500 a month for 20 years | $1,268,841 | $702,526 |
| $2,500 a month for 25 years | $1,957,605 | $934,963 |
| $2,500 a month for 30 years | $2,923,632 | $1,204,497 |
| $2,500 a month for 35 years | $4,278,534 | $1,520,520 |
| $2,500 a month for 40 years | $6,178,855 | $1,894,170 |
Other amounts for 15 years
$50 a month: $15,555, $100 a month: $31,110, $150 a month: $46,666, $200 a month: $62,221, $250 a month: $77,776, $300 a month: $93,331, $400 a month: $124,442, $500 a month: $155,552, $600 a month: $186,663, $750 a month: $233,329, $1,000 a month: $311,105, $1,500 a month: $466,657, $2,000 a month: $622,210, $3,000 a month: $933,314, $5,000 a month: $1,555,524.
How it is worked out
Monthly amounts are deposited at the end of each month and compounded monthly at the rate that equals the annual return; lump sums compound once a year. The headline return is 7% a year, the Trinity-style average the site’s retirement pages use; stock-heavy portfolios have averaged more over long periods and bond-heavy ones less, which is why every page shows 4% to 10%. Today’s dollars divide by 3% inflation a year. The range comes from 1,000 simulated sequences of yearly returns averaging 7% with 12% volatility, with each year’s deposits added through the year. Fees and taxes are not taken out. More on the methodology page.