$600 a month for 20 years at returns from 4% to 10%
| Return | Balance | Of which growth | In today’s dollars |
|---|---|---|---|
| 4% | $218,305 | $74,305 | $120,870 |
| 5% | $243,483 | $99,483 | $134,810 |
| 6% | $272,063 | $128,063 | $150,635 |
| 7% | $304,522 | $160,522 | $168,606 |
| 8% | $341,399 | $197,399 | $189,025 |
| 10% | $430,956 | $286,956 | $238,610 |
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 |
| 4 | $28,800 | $32,981 | $29,303 |
| 5 | $36,000 | $42,718 | $36,849 |
| 6 | $43,200 | $53,136 | $44,500 |
| 7 | $50,400 | $64,284 | $52,268 |
| 8 | $57,600 | $76,212 | $60,162 |
| 9 | $64,800 | $88,975 | $68,192 |
| 10 | $72,000 | $102,631 | $76,367 |
| 11 | $79,200 | $117,243 | $84,699 |
| 12 | $86,400 | $132,879 | $93,198 |
| 13 | $93,600 | $149,608 | $101,876 |
| 14 | $100,800 | $167,509 | $110,743 |
| 15 | $108,000 | $186,663 | $119,812 |
| 16 | $115,200 | $207,157 | $129,094 |
| 17 | $122,400 | $229,087 | $138,601 |
| 18 | $129,600 | $252,551 | $148,347 |
| 19 | $136,800 | $277,658 | $158,344 |
| 20 | $144,000 | $304,522 | $168,606 |
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) |
|---|---|---|---|
| 10 years | $75,622 | $99,307 | $131,277 |
| 20 years | $183,819 | $284,423 | $451,662 |
The middle of the simulation sits below the steady 7% figure of $304,522 because ups and downs cost compounding: a 20% loss needs a 25% gain to get back.
What $304,522 would pay in retirement
At a 4% first-year withdrawal, $304,522 pays about $12,181 a year, $1,015 a month, before tax; in today’s dollars that is about $6,744 a year. How long a balance near it lasts at each withdrawal: how long $300,000 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 |
| 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 |
| $600 a month for 40 years | $1,482,925 | $454,601 |
Other amounts for 20 years
$50 a month: $25,377, $100 a month: $50,754, $150 a month: $76,130, $200 a month: $101,507, $250 a month: $126,884, $300 a month: $152,261, $400 a month: $203,015, $500 a month: $253,768, $750 a month: $380,652, $1,000 a month: $507,536, $1,500 a month: $761,305, $2,000 a month: $1,015,073, $2,500 a month: $1,268,841, $3,000 a month: $1,522,609, $5,000 a month: $2,537,682.
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.