$500 a month for 25 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $254,424 | $104,424 | $121,514 |
| 5% | $292,867 | $142,867 | $139,875 |
| 6% | $338,144 | $188,144 | $161,500 |
| 7% | $391,521 | $241,521 | $186,993 |
| 8% | $454,495 | $304,495 | $217,070 |
| 10% | $616,662 | $466,662 | $294,521 |
Year by year at 7%
| Year | Put in so far | Balance | In today’s dollars |
|---|---|---|---|
| 1 | $6,000 | $6,190 | $6,010 |
| 2 | $12,000 | $12,814 | $12,078 |
| 3 | $18,000 | $19,901 | $18,212 |
| 5 | $30,000 | $35,598 | $30,707 |
| 10 | $60,000 | $85,526 | $63,639 |
| 15 | $90,000 | $155,552 | $99,843 |
| 20 | $120,000 | $253,768 | $140,505 |
| 25 | $150,000 | $391,521 | $186,993 |
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 $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) |
|---|---|---|---|
| 13 years | $85,977 | $120,472 | $168,779 |
| 25 years | $216,232 | $365,160 | $613,579 |
The middle of the simulation sits below the steady 7% figure of $391,521 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $391,521 would pay in retirement
At a 4% first-year withdrawal, $391,521 pays about $15,661 a year, $1,305 a month, before tax; in today’s dollars that is about $7,480 a year. How long a balance near it lasts at each withdrawal: how long $400,000 lasts. To stop saving early and let growth do the rest, see Coast FIRE numbers by age.
$6,000 a year fits in an IRA, whose 2026 limit is $7,500 under 50. See contribution limits, the 401(k) calculator and the Roth IRA calculator.
$500 a month for other terms
| Years | Balance | In today’s dollars |
|---|---|---|
| $500 a month for 5 years | $35,598 | $30,707 |
| $500 a month for 10 years | $85,526 | $63,639 |
| $500 a month for 15 years | $155,552 | $99,843 |
| $500 a month for 20 years | $253,768 | $140,505 |
| 25 years | $391,521 | $186,993 |
| $500 a month for 30 years | $584,726 | $240,899 |
| $500 a month for 35 years | $855,707 | $304,104 |
| $500 a month for 40 years | $1,235,771 | $378,834 |
Other amounts for 25 years
$50 a month: $39,152, $100 a month: $78,304, $150 a month: $117,456, $200 a month: $156,608, $250 a month: $195,760, $300 a month: $234,913, $400 a month: $313,217, $600 a month: $469,825, $750 a month: $587,281, $1,000 a month: $783,042, $1,500 a month: $1,174,563, $2,000 a month: $1,566,084, $2,500 a month: $1,957,605, $3,000 a month: $2,349,126, $5,000 a month: $3,915,209.
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.