$1,000 invested every month at a 7% annual return could grow to about $520,927 in 20 years. You would contribute $240,000; investment growth would add roughly $280,927 — more than the amount you put in.
Where does 7% come from? It’s the approximate long-run real (inflation-adjusted) return of the S&P 500 — about 10% a year in nominal terms since 1926, per long-run data compiled by NYU Stern’s Aswath Damodaran (Source: NYU Stern historical returns).
Model it yourself on our Compound Interest calculator.
The numbers, year by year
| Year | Total contributed | Balance at 7% | Growth |
|---|---|---|---|
| 5 | $60,000 | $71,816 | $11,816 |
| 10 | $120,000 | $173,181 | $53,181 |
| 15 | $180,000 | $317,186 | $137,186 |
| 20 | $240,000 | $520,927 | $280,927 |
By year 20, growth exceeds everything you contributed. Doubling your monthly amount from $500 to $1,000 roughly doubles the final balance — the rate and time horizon matter just as much.
Is $1,000 a month enough for retirement?
Over 20 years it builds about $520,000. Combined with Social Security or other income, that could support roughly $2,000–$2,500 a month in retirement spending using a 4% withdrawal rule. For a fuller picture, read How Much Do I Need to Retire? or use the Retirement calculator.
What if I want a specific goal instead?
If your target is a fixed number — say $1,000,000 — work backwards with our Savings Goal calculator. It tells you the exact monthly amount needed for any goal, rate and time horizon.
Frequently asked questions
What does $1,000 a month look like after inflation?
At 3% inflation, that $520,927 in 20 years buys about what $288,000 buys today. Check the real number with our Inflation calculator.
The 3% figure is the long-run average: CPI-U (the Consumer Price Index for All Urban Consumers) has compounded at roughly 3% a year since 1913 (Source: U.S. Bureau of Labor Statistics CPI).
Is a monthly plan better than waiting for a lump sum?
For most people, consistent monthly investing is easier to sustain than saving up a lump sum. Compare the two in our DCA vs Lump Sum calculator.
Should I use a retirement account?
Tax-advantaged accounts can improve the after-tax result significantly. This projection is before tax — consider the account type in your plan.