$750 a month for 15 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $183,493 | $48,493 | $117,777 |
| 5% | $198,618 | $63,618 | $127,486 |
| 6% | $215,184 | $80,184 | $138,118 |
| 7% | $233,329 | $98,329 | $149,765 |
| 8% | $253,205 | $118,205 | $162,522 |
| 10% | $298,833 | $163,833 | $191,810 |
Year by year at 7%
| Year | Put in so far | Balance | In today’s dollars |
|---|---|---|---|
| 1 | $9,000 | $9,285 | $9,015 |
| 2 | $18,000 | $19,220 | $18,117 |
| 3 | $27,000 | $29,851 | $27,318 |
| 4 | $36,000 | $41,226 | $36,629 |
| 5 | $45,000 | $53,397 | $46,061 |
| 6 | $54,000 | $66,420 | $55,626 |
| 7 | $63,000 | $80,355 | $65,336 |
| 8 | $72,000 | $95,265 | $75,203 |
| 9 | $81,000 | $111,218 | $85,240 |
| 10 | $90,000 | $128,289 | $95,459 |
| 11 | $99,000 | $146,554 | $105,874 |
| 12 | $108,000 | $166,098 | $116,498 |
| 13 | $117,000 | $187,010 | $127,345 |
| 14 | $126,000 | $209,386 | $138,429 |
| 15 | $135,000 | $233,329 | $149,765 |
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 $750 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) |
|---|---|---|---|
| 8 years | $72,999 | $93,776 | $118,272 |
| 15 years | $154,979 | $222,960 | $317,019 |
The middle of the simulation sits below the steady 7% figure of $233,329 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $233,329 would pay in retirement
At a 4% first-year withdrawal, $233,329 pays about $9,333 a year, $778 a month, before tax; in today’s dollars that is about $5,991 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.
$9,000 a year is more than the 2026 IRA limit of $7,500 but fits in a 401(k), 403(b) or TSP, whose limit is $24,500. See contribution limits, the 401(k) calculator and the Roth IRA calculator.
$750 a month for other terms
| Years | Balance | In today’s dollars |
|---|---|---|
| $750 a month for 5 years | $53,397 | $46,061 |
| $750 a month for 10 years | $128,289 | $95,459 |
| 15 years | $233,329 | $149,765 |
| $750 a month for 20 years | $380,652 | $210,758 |
| $750 a month for 25 years | $587,281 | $280,489 |
| $750 a month for 30 years | $877,089 | $361,349 |
| $750 a month for 35 years | $1,283,560 | $456,156 |
| $750 a month for 40 years | $1,853,657 | $568,251 |
Other amounts for 15 years
$50 a month: $15,555, $100 a month: $31,110, $150 a month: $46,666, $200 a month: $62,221, $250 a month: $77,776, $300 a month: $93,331, $400 a month: $124,442, $500 a month: $155,552, $600 a month: $186,663, $1,000 a month: $311,105, $1,500 a month: $466,657, $2,000 a month: $622,210, $2,500 a month: $777,762, $3,000 a month: $933,314, $5,000 a month: $1,555,524.
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.