$250 a month for 15 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $61,164 | $16,164 | $39,259 |
| 5% | $66,206 | $21,206 | $42,495 |
| 6% | $71,728 | $26,728 | $46,039 |
| 7% | $77,776 | $32,776 | $49,922 |
| 8% | $84,402 | $39,402 | $54,174 |
| 10% | $99,611 | $54,611 | $63,937 |
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 |
| 4 | $12,000 | $13,742 | $12,210 |
| 5 | $15,000 | $17,799 | $15,354 |
| 6 | $18,000 | $22,140 | $18,542 |
| 7 | $21,000 | $26,785 | $21,779 |
| 8 | $24,000 | $31,755 | $25,068 |
| 9 | $27,000 | $37,073 | $28,413 |
| 10 | $30,000 | $42,763 | $31,820 |
| 11 | $33,000 | $48,851 | $35,291 |
| 12 | $36,000 | $55,366 | $38,833 |
| 13 | $39,000 | $62,337 | $42,448 |
| 14 | $42,000 | $69,795 | $46,143 |
| 15 | $45,000 | $77,776 | $49,922 |
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) |
|---|---|---|---|
| 8 years | $24,333 | $31,259 | $39,424 |
| 15 years | $51,660 | $74,320 | $105,673 |
The middle of the simulation sits below the steady 7% figure of $77,776 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $77,776 would pay in retirement
At a 4% first-year withdrawal, $77,776 pays about $3,111 a year, $259 a month, before tax; in today’s dollars that is about $1,997 a year. How long a balance near it lasts at each withdrawal: how long $100,000 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 |
| 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 |
| $250 a month for 40 years | $617,886 | $189,417 |
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, $300 a month: $93,331, $400 a month: $124,442, $500 a month: $155,552, $600 a month: $186,663, $750 a month: $233,329, $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.