Compound interest calculator
Calculate monthly compound growth from an initial amount and a nominal annual return, with a balance table. Free in your browser.
The annual return is a nominal annual rate. Monthly rate = annual rate ÷ 100 ÷ 12, compounded monthly. Use the same currency for all amounts.
- Final amount
- Initial amount
- Accumulated return
Actual returns vary. Taxes, fees, and inflation are excluded. Only displayed amounts are rounded to two decimal places.
Up to 12 months: monthly rows. Longer periods: annual summaries (multiple-year intervals for very long periods), including the initial and final balances.
| Month | Final amount | Initial amount | Accumulated return |
|---|---|---|---|
| 0 | 1,000 | 1,000 | 0 |
| 1 | 1,010 | 1,000 | 10 |
| 2 | 1,020.1 | 1,000 | 20.1 |
| 3 | 1,030.3 | 1,000 | 30.3 |
| 4 | 1,040.6 | 1,000 | 40.6 |
| 5 | 1,051.01 | 1,000 | 51.01 |
| 6 | 1,061.52 | 1,000 | 61.52 |
| 7 | 1,072.14 | 1,000 | 72.14 |
| 8 | 1,082.86 | 1,000 | 82.86 |
| 9 | 1,093.69 | 1,000 | 93.69 |
| 10 | 1,104.62 | 1,000 | 104.62 |
| 11 | 1,115.67 | 1,000 | 115.67 |
| 12 | 1,126.83 | 1,000 | 126.83 |
Your inputs stay on this device.
How to use
- Enter an initial amount and a nonnegative nominal annual return.
- Enter a whole number of months (0–120,000).
- Review the final amount, return, and balance table; copy the conditions and results.
With P as the initial amount, r = annual return / 100 / 12, and n months, balance = P × (1 + r)^n. For 1,000 at 12% over one month, the result is 1,010. There are no monthly deposits. Calculations run in your browser without uploads.