$500 a month for 20 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $181,921 | $61,921 | $100,725 |
| 5% | $202,902 | $82,902 | $112,342 |
| 6% | $226,719 | $106,719 | $125,529 |
| 7% | $253,768 | $133,768 | $140,505 |
| 8% | $284,500 | $164,500 | $157,520 |
| 10% | $359,130 | $239,130 | $198,841 |
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 |
| 4 | $24,000 | $27,484 | $24,419 |
| 5 | $30,000 | $35,598 | $30,707 |
| 6 | $36,000 | $44,280 | $37,084 |
| 7 | $42,000 | $53,570 | $43,557 |
| 8 | $48,000 | $63,510 | $50,135 |
| 9 | $54,000 | $74,146 | $56,826 |
| 10 | $60,000 | $85,526 | $63,639 |
| 11 | $66,000 | $97,703 | $70,583 |
| 12 | $72,000 | $110,732 | $77,665 |
| 13 | $78,000 | $124,674 | $84,897 |
| 14 | $84,000 | $139,591 | $92,286 |
| 15 | $90,000 | $155,552 | $99,843 |
| 16 | $96,000 | $172,631 | $107,578 |
| 17 | $102,000 | $190,906 | $115,501 |
| 18 | $108,000 | $210,459 | $123,623 |
| 19 | $114,000 | $231,381 | $131,954 |
| 20 | $120,000 | $253,768 | $140,505 |
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) |
|---|---|---|---|
| 10 years | $63,018 | $82,755 | $109,397 |
| 20 years | $153,182 | $237,019 | $376,385 |
The middle of the simulation sits below the steady 7% figure of $253,768 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $253,768 would pay in retirement
At a 4% first-year withdrawal, $253,768 pays about $10,151 a year, $846 a month, before tax; in today’s dollars that is about $5,620 a year. How long a balance near it lasts at each withdrawal: how long $250,000 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 |
| 20 years | $253,768 | $140,505 |
| $500 a month for 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 20 years
$50 a month: $25,377, $100 a month: $50,754, $150 a month: $76,130, $200 a month: $101,507, $250 a month: $126,884, $300 a month: $152,261, $400 a month: $203,015, $600 a month: $304,522, $750 a month: $380,652, $1,000 a month: $507,536, $1,500 a month: $761,305, $2,000 a month: $1,015,073, $2,500 a month: $1,268,841, $3,000 a month: $1,522,609, $5,000 a month: $2,537,682.
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.