Investment Growth Calculator
Project how an investment portfolio grows when you invest a fixed amount each month.
Want to understand the concept, not just the number? Read The Compound Interest Guide and more below.
| Year | Start | Contributions | Growth | End |
|---|---|---|---|---|
| 1 | $5,000 | $6,000 | $640 | $11,640 |
| 2 | $11,640 | $6,000 | $1,191 | $18,831 |
| 3 | $18,831 | $6,000 | $1,788 | $26,619 |
| 4 | $26,619 | $6,000 | $2,434 | $35,053 |
| 5 | $35,053 | $6,000 | $3,134 | $44,188 |
| 6 | $44,188 | $6,000 | $3,893 | $54,080 |
| 7 | $54,080 | $6,000 | $4,714 | $64,794 |
| 8 | $64,794 | $6,000 | $5,603 | $76,397 |
| 9 | $76,397 | $6,000 | $6,566 | $88,962 |
| 10 | $88,962 | $6,000 | $7,609 | $102,571 |
| 11 | $102,571 | $6,000 | $8,738 | $117,310 |
| 12 | $117,310 | $6,000 | $9,962 | $133,271 |
| 13 | $133,271 | $6,000 | $11,286 | $150,558 |
| 14 | $150,558 | $6,000 | $12,721 | $169,279 |
| 15 | $169,279 | $6,000 | $14,275 | $189,554 |
| 16 | $189,554 | $6,000 | $15,958 | $211,512 |
| 17 | $211,512 | $6,000 | $17,780 | $235,292 |
| 18 | $235,292 | $6,000 | $19,754 | $261,046 |
| 19 | $261,046 | $6,000 | $21,892 | $288,938 |
| 20 | $288,938 | $6,000 | $24,207 | $319,144 |
| 21 | $319,144 | $6,000 | $26,714 | $351,858 |
| 22 | $351,858 | $6,000 | $29,429 | $387,287 |
| 23 | $387,287 | $6,000 | $32,370 | $425,657 |
| 24 | $425,657 | $6,000 | $35,554 | $467,211 |
| 25 | $467,211 | $6,000 | $39,003 | $512,214 |
Range of outcomes
The projection above uses a single steady return, so it draws one smooth line. Real markets rise and fall from year to year, and the order of those swings changes where you end up. This simulation runs 500 separate paths, giving each year a random return centered on your expected rate, then sorts the results from worst to best.
The three figures below are the outcomes at the 10th, 50th, and 90th percentiles. The median is the middle result, with half of the paths above it and half below. It usually lands under the smooth projection, because market swings drag on compound growth. Past performance never guarantees future returns, so treat this as a range to plan around rather than a promise.
Simulating a range of outcomes...
How it's calculated
Investing a fixed amount every month is called dollar-cost averaging. It buys more shares when prices are low and fewer when they are high, so you never have to time the market. This calculator models the balance compounding monthly at your expected return.
For example, $10,000 invested at a 7% annual return with monthly compounding grows to $20,096.61 in 10 years on its own. Adding a steady monthly investment on top of that pushes the total much higher over a few decades, since each contribution compounds for the rest of the time horizon.
This uses a single steady return, so it draws a smooth curve rather than the ups and downs of a real market. Read it as a long-run average outcome, not a prediction for any single year.
Assumptions
- Returns compound monthly, and investments are made at month end, which models dollar-cost averaging.
Last updated: 2026-08-07
These assumptions follow our general methodology.
Frequently asked questions
Does this account for market volatility?
The main projection uses a steady average return, so it draws a smooth line. For a range of outcomes based on market ups and downs, open the Monte Carlo panel on this page. It runs hundreds of random return paths and shows the 10th, 50th, and 90th percentile balances.
What is dollar-cost averaging?
It is investing a fixed dollar amount on a regular schedule, whatever the price. Over time your average cost per share smooths out, and you avoid the risk of putting everything in at a market peak.
What return should I expect?
A diversified, stock-heavy portfolio has historically averaged around 7% a year after inflation over long periods. That is an average across good and bad years, not a guarantee, so it is wise to check a lower figure too.
How is this different from the compound interest calculator?
They share the same engine. This one is framed for investing a fixed amount every month at an expected market return, while the Compound Interest calculator is more general. To compare investing a lump sum against spreading it out, use the Dollar-Cost Averaging vs Lump Sum calculator.
Do investment fees change the result?
Yes, and more than most people expect. A 1% annual fee can quietly cost you a large share of your final balance over decades. Enter your return net of fees here, or see the full effect in the Investment Fee calculator.