$250 a month for 40 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $290,266 | $170,266 | $88,983 |
| 5% | $370,631 | $250,631 | $113,620 |
| 6% | $476,919 | $356,919 | $146,203 |
| 7% | $617,886 | $497,886 | $189,417 |
| 8% | $805,270 | $685,270 | $246,861 |
| 10% | $1,387,587 | $1,267,587 | $425,374 |
Year by year at 7%
| Year | Put in so far | Balance | In today’s dollars |
|---|---|---|---|
| 1 | $3,000 | $3,095 | $3,005 |
| 2 | $6,000 | $6,407 | $6,039 |
| 3 | $9,000 | $9,950 | $9,106 |
| 5 | $15,000 | $17,799 | $15,354 |
| 10 | $30,000 | $42,763 | $31,820 |
| 15 | $45,000 | $77,776 | $49,922 |
| 20 | $60,000 | $126,884 | $70,253 |
| 25 | $75,000 | $195,760 | $93,496 |
| 30 | $90,000 | $292,363 | $120,450 |
| 35 | $105,000 | $427,853 | $152,052 |
| 40 | $120,000 | $617,886 | $189,417 |
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 $250 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 | $76,591 | $118,510 | $188,192 |
| 40 years | $272,229 | $540,785 | $1,077,485 |
The middle of the simulation sits below the steady 7% figure of $617,886 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $617,886 would pay in retirement
At a 4% first-year withdrawal, $617,886 pays about $24,715 a year, $2,060 a month, before tax; in today’s dollars that is about $7,577 a year. How long a balance near it lasts at each withdrawal: how long $600,000 lasts. To stop saving early and let growth do the rest, see Coast FIRE numbers by age.
$3,000 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.
$250 a month for other terms
| Years | Balance | In today’s dollars |
|---|---|---|
| $250 a month for 5 years | $17,799 | $15,354 |
| $250 a month for 10 years | $42,763 | $31,820 |
| $250 a month for 15 years | $77,776 | $49,922 |
| $250 a month for 20 years | $126,884 | $70,253 |
| $250 a month for 25 years | $195,760 | $93,496 |
| $250 a month for 30 years | $292,363 | $120,450 |
| $250 a month for 35 years | $427,853 | $152,052 |
| 40 years | $617,886 | $189,417 |
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, $300 a month: $741,463, $400 a month: $988,617, $500 a month: $1,235,771, $600 a month: $1,482,925, $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.