What is compound interest?

Interest earned on both the principal amount and previously accumulated interest. Over time, compounding accelerates growth — this is why starting early is so powerful.

What compounding frequencies are supported?

Annually, semi-annually, quarterly, monthly, and daily. More frequent compounding yields slightly more interest.

Can I include regular contributions?

Yes. Enable the "Add regular contributions" option and specify a monthly or yearly contribution amount. The calculator shows the impact of regular savings on your final balance.

What is the return multiple?

The ratio of final balance to total contributions. For example, 2x means your money doubled from contributions alone (the rest is interest earned).

Compound Interest Calculator

Free online compound interest calculator. Calculate compound interest with regular monthly or yearly contributions. See year-by-year growth. Free, no signup, supports multiple currencies.

Compound Interest Calculator

Calculate compound interest with regular contributions. See how your investment grows year by year. Free, no signup.

Initial investment (principal)

Currency

Annual interest rate (%)

Number of years

Compounding frequency

Add regular contributions

Contribution amount

Contribution frequency

How to Use the Compound Interest Calculator

1Enter the principal amount, annual interest rate and time period.
2Set the compounding frequency — monthly, quarterly or yearly.
3Add optional monthly contributions to model a savings plan.
4Review the year-by-year growth table separating your deposits from earned interest.