ScanSpotCompound Interest
See what a starting balance plus regular deposits grows into over time.
✅ No signup · ✅ Free forever · ✅ Files never leave your device
💹 Compound Interest
What a starting balance plus monthly deposits grows into, with a year-by-year table.
See what a starting balance plus a regular monthly deposit grows into. Enter the opening amount, any monthly contribution, the annual interest rate, the number of years and how often interest compounds, and the calculator returns the final balance, how much of it you contributed and how much is interest. Compounding frequency matters: the same headline rate paid monthly produces a slightly higher effective return than the same rate paid once a year.
How to use the Compound Interest
- Enter the starting balance — use zero to model saving from nothing.
- Add a monthly deposit if you contribute regularly.
- Set the annual interest rate and choose how often interest compounds.
- Read the final balance, then scroll the table to see how much of it is interest rather than contributions.
Why people use it
- Retirement planning: the table shows why early contributions matter far more than late ones.
- Comparing accounts: same headline rate, different compounding, different result.
- Teaching: the year-by-year rows make the curve visible instead of theoretical.
- Sanity-checking a savings illustration a bank or adviser handed you.
Frequently asked questions
Is the annual rate the same as the effective annual rate?
No. If a 6% annual rate compounds monthly, the effective annual return is roughly 6.17%, because interest starts earning interest within the year. The higher the rate and the more frequent the compounding, the wider the gap.
When is the monthly deposit added?
This calculator adds each deposit at the end of the month, so it starts earning interest the following month. Depositing at the start of the month instead produces a slightly higher total.
Does it account for inflation, fees or tax?
No, all three reduce real returns. To approximate, subtract your expected inflation rate from the interest rate and run the calculation with a net-of-fee rate. Treat the output as a projection, not a promise — investment returns are not fixed.