This calculator projects the balance you'd build from a lump sum plus a fixed monthly contribution. Start with $20,000, add $500 a month at 7% a year, and you'd have $772,315 after 30 years.
Only $200,000 of that is money you put in. The rest is growth, and growth is the part that fees and inflation eat into.
How the projection is built
Each contribution arrives at the end of its month and earns from then on. Returns compound monthly at one twelfth of the yearly rate, so 7% works out to about 7.23% a year.
That matters if your 7% is a yearly growth figure, such as a fund's past annual return. Entered here, it slightly overstates growth. The return also stays the same every month, with no fees, taxes or inflation.
Your money versus the growth
Early on, the balance is mostly what you've paid in. Later, growth takes over. Here's the plan at 7%, at 6% after a fee, and with no growth at all:
$20,000 plus $500 a month for 30 years
Balance at the end of each year, compounded monthly
- 7% a year, no fee $772,315
- 6% a year, after a 1% fee $622,709
- Contributions only $200,000
Show the balances
| Year | 7% a year, no fee | 6% a year, after a 1% fee | Contributions only |
|---|---|---|---|
| 5 | $64,149 | $61,862 | $50,000 |
| 10 | $126,736 | $118,328 | $80,000 |
| 20 | $341,238 | $297,225 | $140,000 |
| 30 | $772,315 | $622,709 | $200,000 |
After 10 years at 7%, you'd have $126,736, and $80,000 of it would be your own contributions. By year 30, growth is nearly three quarters of the balance. The last decade adds more than the first two combined.
Fees compound against you
An annual fee charged as a share of your balance compounds just as returns do. The SEC's bulletin on fees shows $100,000 growing at 4% a year for 20 years. With a 0.25% fee, it ends near $208,000; with a 1% fee, near $179,000.
To include a fee here, subtract it from the return you enter. For the plan above:
| Annual fee | Return to enter | Balance after 30 years | Growth beyond what you paid in |
|---|---|---|---|
| None | 7% | $772,315 | $572,315 |
| 0.25% | 6.75% | $731,398 | $531,398 |
| 1% | 6% | $622,709 | $422,709 |
The 1% fee costs $149,606 by year 30: the fees themselves plus the growth they would have earned. Find a fund's yearly cost with the expense ratio calculator, or see it in dollars with the investment fee calculator.
What the balance will buy
A dollar in 30 years won't stretch as far as one today. The Bureau of Labor Statistics' reading for August 2026 put the 12-month rise in consumer prices at 3.4%.
To measure the result in current dollars, turn your return into a real return first:
At 3.4% inflation, 7% becomes 3.48% and 6% becomes 2.51%. Enter those, and the table shows the plan at today's prices. It treats your $500 as rising with inflation, so it keeps its buying power:
| Scenario | Real return to enter | Balance at today's prices |
|---|---|---|
| 7% return, no fee, 3.4% inflation | 3.48% | $373,323 |
| 6% after a 1% fee, 3.4% inflation | 2.51% | $310,567 |
| 6% after a 1% fee, 2% inflation | 3.92% | $406,822 |
After a 1% fee and 3.4% inflation, $772,315 shrinks to $310,567 of today's buying power. One year's inflation reading isn't a forecast, though. Whether inflation averages 2% or 3.4% moves that result by almost $100,000.
If your $500 stays fixed instead, the real figure is lower. Divide the nominal balance by 1.034^30: $622,709 is worth about $228,000 at today's prices.
One steady return is a simplification
Markets don't deliver the same return every month. With regular contributions, the order of good and bad years matters. A fall late in the plan hits a bigger balance.
So run your plan at a lower return too, and treat the gap between the two results as your range. Taxes aren't included either, so use an after-tax return for a taxable account.