$500 a month for 40 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $580,532 | $340,532 | $177,966 |
| 5% | $741,262 | $501,262 | $227,239 |
| 6% | $953,839 | $713,839 | $292,406 |
| 7% | $1,235,771 | $995,771 | $378,834 |
| 8% | $1,610,540 | $1,370,540 | $493,722 |
| 10% | $2,775,174 | $2,535,174 | $850,749 |
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 |
| 5 | $30,000 | $35,598 | $30,707 |
| 10 | $60,000 | $85,526 | $63,639 |
| 15 | $90,000 | $155,552 | $99,843 |
| 20 | $120,000 | $253,768 | $140,505 |
| 25 | $150,000 | $391,521 | $186,993 |
| 30 | $180,000 | $584,726 | $240,899 |
| 35 | $210,000 | $855,707 | $304,104 |
| 40 | $240,000 | $1,235,771 | $378,834 |
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) |
|---|---|---|---|
| 20 years | $153,182 | $237,019 | $376,385 |
| 40 years | $544,457 | $1,081,570 | $2,154,970 |
The middle of the simulation sits below the steady 7% figure of $1,235,771 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $1,235,771 would pay in retirement
At a 4% first-year withdrawal, $1,235,771 pays about $49,431 a year, $4,119 a month, before tax; in today’s dollars that is about $15,153 a year. How long a balance near it lasts at each withdrawal: how long $1.25 million 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 |
| $500 a month for 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 |
| 40 years | $1,235,771 | $378,834 |
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, $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.