$2,500 a month for 10 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $366,740 | $66,740 | $272,889 |
| 5% | $385,908 | $85,908 | $287,152 |
| 6% | $406,184 | $106,184 | $302,239 |
| 7% | $427,629 | $127,629 | $318,196 |
| 8% | $450,311 | $150,311 | $335,073 |
| 10% | $499,660 | $199,660 | $371,794 |
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 |
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) |
|---|---|---|---|
| 5 years | $145,199 | $175,375 | $213,500 |
| 10 years | $315,091 | $413,777 | $546,986 |
The middle of the simulation sits below the steady 7% figure of $427,629 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $427,629 would pay in retirement
At a 4% first-year withdrawal, $427,629 pays about $17,105 a year, $1,425 a month, before tax; in today’s dollars that is about $12,728 a year. How long a balance near it lasts at each withdrawal: how long $450,000 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 |
| 10 years | $427,629 | $318,196 |
| $2,500 a month for 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 10 years
$50 a month: $8,553, $100 a month: $17,105, $150 a month: $25,658, $200 a month: $34,210, $250 a month: $42,763, $300 a month: $51,316, $400 a month: $68,421, $500 a month: $85,526, $600 a month: $102,631, $750 a month: $128,289, $1,000 a month: $171,052, $1,500 a month: $256,578, $2,000 a month: $342,103, $3,000 a month: $513,155, $5,000 a month: $855,259.
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.