Investment Calculator
Enter a starting amount, a monthly contribution, a return and a time to see what your investment could grow to.
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Project the future value of an investment with monthly contributions.
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How investment growth is calculated
This investment calculator shows what a starting amount plus regular monthly contributions could grow to at a constant annual return, compounded monthly. Each month your balance earns a month’s worth of the annual rate and then your contribution is added. The more years you invest, the more of the final balance comes from growth rather than from your own deposits. Returns are not guaranteed, and real markets go up and down; a fixed rate is a planning assumption.
Example: $10,000 plus $500 a month
| Time | Annual return | You contribute | Future value |
|---|---|---|---|
| 10 years | 5% | $70,000 | $94,111 |
| 10 years | 7% | $70,000 | $106,639 |
| 10 years | 9% | $70,000 | $121,271 |
| 20 years | 5% | $130,000 | $232,643 |
| 20 years | 7% | $130,000 | $300,851 |
| 20 years | 9% | $130,000 | $394,035 |
| 30 years | 5% | $190,000 | $460,807 |
| 30 years | 7% | $190,000 | $691,150 |
| 30 years | 9% | $190,000 | $1,062,678 |
Ways to grow more
- Start early: time matters more than the exact return. Compare 10, 20 and 30 years in the table.
- Contribute regularly: even small monthly amounts add up when compounded.
- Watch fees: a 1% annual fee lowers your effective return by about 1 percentage point every year.
- Use tax-advantaged accounts such as a 401(k) or IRA when they are available to you; see the 401(k) calculator and the Roth IRA calculator.
This is a projection for planning, not a promise and not financial advice. It ignores taxes and inflation; compare with the inflation calculator and the compound interest calculator.
How to use the investment calculator
- Enter your starting amount and your monthly contribution.
- Enter the expected annual return and the number of years.
- Read the future value, how much you contributed and how much is growth.
Frequently asked questions
How much will $500 a month grow to?
It depends on the return and the time. For example, $10,000 plus $500 a month at 7% for 20 years grows to about $300,851, of which you contribute $130,000.
What annual return should I assume?
No return is guaranteed. Many people test a range, such as 5%, 7% and 9%, to see how sensitive the result is. Lower returns are the safer planning assumption.
Does this include taxes and inflation?
No. The result is a nominal projection before taxes, fees and inflation. Inflation reduces what the future amount can buy.
How often is the growth compounded?
Monthly: each month the balance earns one twelfth of the annual rate and then the monthly contribution is added.
Is the starting amount required?
No. You can leave it at zero and enter only a monthly contribution.
Related tools: Compound interest calculator · 401(k) calculator · Retirement calculator