What happens if you invest $1,000 a month
Investing $1,000 a month at an 8% average annual return grows to about $1,490,359 after 30 years, from just $360,000 of your own money. Here is the full picture.
Growth table: $1,000 a month
| Time | You put in | At 6% | At 8% | At 10% |
|---|---|---|---|---|
| 5 years | $60,000 | $69,770 | $73,477 | $77,437 |
| 10 years | $120,000 | $163,879 | $182,946 | $204,845 |
| 15 years | $180,000 | $290,819 | $346,038 | $414,470 |
| 20 years | $240,000 | $462,041 | $589,020 | $759,369 |
| 25 years | $300,000 | $692,994 | $951,026 | $1,326,833 |
| 30 years | $360,000 | $1,004,515 | $1,490,359 | $2,260,488 |
| 35 years | $420,000 | $1,424,710 | $2,293,882 | $3,796,638 |
| 40 years | $480,000 | $1,991,491 | $3,491,008 | $6,324,080 |
Monthly contributions at month end, returns compounded monthly, no taxes or fees. Starting balance $0.
How long until you're a millionaire?
Investing $1,000 a month from scratch, you would reach $1,000,000 in about 30.0 years at 6%, 25.6 years at 8%, or 22.5 years at 10%.
Why the last decade matters most
Look at the 8% column. Going from 30 to 40 years adds more than the first 20 years combined. That's compounding: in later years, growth on your existing balance far exceeds your contributions. Starting earlier beats investing more later.
Want to add a starting balance or raise your contribution each year? Try the compound interest calculator with $1,000/month pre-filled.
Where to invest $1,000 a month
For most people, a low-cost, broadly diversified index fund (a total US market or S&P 500 fund, often paired with an international fund) inside a tax-advantaged account is the simplest place to start. Many brokers let you schedule automatic monthly investments, including fractional shares.
Common questions
How much will $1,000 a month be worth in 20 years?
About $589,020 at an 8% annual return, $462,041 at 6%, or $759,369 at 10%. You would have contributed $240,000.
Is an 8% return realistic?
The US stock market has returned about 10% a year nominally over the long run, but with big swings and decade-long flat stretches. 6–8% is a common planning assumption for a stock-heavy portfolio.