Compound interest calculator
A starting sum, monthly deposits and an annual rate, with the balance shown year by year.
- Runs on your device
- No sign-up
- Works offline after a visit
| Year | Contributed so far | Interest so far | Balance |
|---|
Contributions are added at the end of each month.
How to work out how savings grow
- Enter the starting amount, the monthly contribution and the annual rate.
- Set the number of years, then choose how often the interest compounds.
- Read the final balance, then scan the year-by-year table.
Questions
What is compound interest?
Interest paid on the money you put in and on the interest already earned. Each period’s interest joins the balance, so the next period earns interest on a larger amount.
Does compounding more often always give more?
At the same stated rate, yes, but only slightly. Interest starts earning interest sooner, so the effective yearly rate rises as compounding becomes more frequent.
When are the monthly contributions added?
At the end of each month, after that month’s interest. The calculator does the same month by month, whichever compounding you pick.
Is the result a guaranteed return?
No. It applies the rate you enter every year from start to finish. Real savings and investments can change rate, charge fees or fall in value, so treat the figure as an estimate.