Investment Calculator · Practical guide
$500 a Month Invested for 30 Years
Invest $500 a month at 8% and 30 years later you'll have about $750,148 — on just $180,000 of deposits.
At a glance
The Answer: About $750,148 at 8%
Invest $500 every month for 30 years at an 8% average annual return and you'll end with $750,147.59. You deposited only $180,000 of that (360 payments of $500); the remaining $570,148 — about 76% of the total — is pure investment growth from compounding.
Interactive tool
Investment Calculator
Enter your own values, then compare the result with the examples below.
Investment Summary
Year-by-Year Growth
| Year | Start Balance | Contributions | Returns | End Balance |
|---|
Same $500 a Month, Different Returns
| Annual Return | After 20 Years | After 30 Years | After 40 Years |
|---|---|---|---|
| 6% | $232,176 | $504,769 | $1,000,724 |
| 7% | $261,983 | $613,544 | $1,320,062 |
| 8% | $296,474 | $750,148 | $1,757,141 |
| 10% | $382,848 | $1,139,663 | $3,188,390 |
Note how time magnifies the rate gap: at 20 years, 10% beats 6% by about $150,000; at 40 years, by more than $2.1 million — on identical deposits of $240,000.
Why the Growth Accelerates
In year 1, your $6,000 of deposits does almost all the work and returns add little. But compounding snowballs: annual returns eventually overtake your annual contributions, and by year 30 at 8% the portfolio earns more in a single year than you deposit in nearly nine. This is why the calculator shows a year-by-year table — the back half of the curve is where wealth is actually built.
Make It Realistic
These are pre-tax, pre-fee projections at a steady return; real markets zigzag. A 1% fund fee alone would cut the 8% result from $750,148 to roughly $607,000 — model it by entering 7% instead of 8%. And $750,148 in 30 years buys what about $309,000 buys today if inflation averages 3%. Even so, the habit of $500 a month beats almost any one-time deposit strategy available to most savers.
Frequently Asked Questions
Is $500 a month enough to retire on?
It builds a substantial nest egg — about $750,000 over 30 years at 8% — but whether that's enough depends on your retirement spending. A common rule suggests withdrawing about 4% a year, which would provide roughly $30,000 annually from that balance.
What if I can only invest $250 a month?
Everything scales linearly with the contribution: $250 a month for 30 years at 8% yields about $375,074, exactly half of the $500 result. Enter your real number in the calculator.
Should I invest monthly or in a lump sum?
If you already have the cash, lump-sum investing wins mathematically most of the time because markets rise more often than they fall. But for most people, monthly investing is simply how paychecks arrive, and it reduces the risk of investing everything right before a downturn.
Where do I actually invest $500 a month?
Common choices are a 401(k) up to the employer match, then an IRA, then a taxable brokerage account — typically in low-cost, broadly diversified index funds. Tax-advantaged accounts keep more of the growth shown here.