Compound Interest Calculator
See how a one-time deposit grows when interest is added to the balance and then earns interest itself.
- Final amount
- –
- Interest earned
- –
- Effective yearly rate
- –
How it is calculated
- A = P × (1 + r ÷ n)^(n × t)
- P = starting amount, r = yearly rate ÷ 100, n = times interest is added per year, t = years
- Effective yearly rate = (1 + r ÷ n)^n − 1
Worked example
1,000 at 5% a year, interest added monthly, for 10 years.
| You enter | |
|---|---|
| Starting amount | 1,000 |
| Interest rate per year | 5 % |
| Years | 10 |
| Interest added | Monthly |
| You get | |
| Final amount | 1,647.01 |
| Interest earned | 647.01 |
| Effective yearly rate | 5.1162% |
Questions
Does it include tax on profit?
No. Withholding tax on profit (for example on bank deposits or savings certificates) reduces what you keep.
Sources and checks
Last checked: 12 October 2026. This calculator passes 4 automatic tests before every release.
Results are estimates for information only and are not financial, tax or legal advice. Check important figures with a qualified professional before you act on them.