$600 a month for 40 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $696,638 | $408,638 | $213,559 |
| 5% | $889,515 | $601,515 | $272,687 |
| 6% | $1,144,607 | $856,607 | $350,887 |
| 7% | $1,482,925 | $1,194,925 | $454,601 |
| 8% | $1,932,648 | $1,644,648 | $592,466 |
| 10% | $3,330,209 | $3,042,209 | $1,020,898 |
Year by year at 7%
| Year | Put in so far | Balance | In today’s dollars |
|---|---|---|---|
| 1 | $7,200 | $7,428 | $7,212 |
| 2 | $14,400 | $15,376 | $14,494 |
| 3 | $21,600 | $23,881 | $21,854 |
| 5 | $36,000 | $42,718 | $36,849 |
| 10 | $72,000 | $102,631 | $76,367 |
| 15 | $108,000 | $186,663 | $119,812 |
| 20 | $144,000 | $304,522 | $168,606 |
| 25 | $180,000 | $469,825 | $224,391 |
| 30 | $216,000 | $701,672 | $289,079 |
| 35 | $252,000 | $1,026,848 | $364,925 |
| 40 | $288,000 | $1,482,925 | $454,601 |
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 $600 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) |
|---|---|---|---|
| 20 years | $183,819 | $284,423 | $451,662 |
| 40 years | $653,349 | $1,297,884 | $2,585,964 |
The middle of the simulation sits below the steady 7% figure of $1,482,925 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $1,482,925 would pay in retirement
At a 4% first-year withdrawal, $1,482,925 pays about $59,317 a year, $4,943 a month, before tax; in today’s dollars that is about $18,184 a year. How long a balance near it lasts at each withdrawal: how long $1.5 million lasts. To stop saving early and let growth do the rest, see Coast FIRE numbers by age.
$7,200 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.
$600 a month for other terms
| Years | Balance | In today’s dollars |
|---|---|---|
| $600 a month for 5 years | $42,718 | $36,849 |
| $600 a month for 10 years | $102,631 | $76,367 |
| $600 a month for 15 years | $186,663 | $119,812 |
| $600 a month for 20 years | $304,522 | $168,606 |
| $600 a month for 25 years | $469,825 | $224,391 |
| $600 a month for 30 years | $701,672 | $289,079 |
| $600 a month for 35 years | $1,026,848 | $364,925 |
| 40 years | $1,482,925 | $454,601 |
Other amounts for 40 years
$50 a month: $123,577, $100 a month: $247,154, $150 a month: $370,731, $200 a month: $494,308, $250 a month: $617,886, $300 a month: $741,463, $400 a month: $988,617, $500 a month: $1,235,771, $750 a month: $1,853,657, $1,000 a month: $2,471,542, $1,500 a month: $3,707,313, $2,000 a month: $4,943,084, $2,500 a month: $6,178,855, $3,000 a month: $7,414,626, $5,000 a month: $12,357,710.
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.