How to use the Compound Interest Calculator in a few steps
The Compound Interest Calculator is designed so a typical projection takes under a minute. Follow these steps.
Step 1: Enter principal, rate, and years
Type the starting amount (your principal), the annual interest rate, and the number of years you want to project.
Step 2: Choose a compounding frequency
Select annual, quarterly, or monthly compounding. Pick the one your bank or deposit uses so the projection matches reality.
Step 3: Add monthly contributions and read the chart
If you add to the account regularly, enter the monthly contribution. The growth chart then shows your balance year by year, with the pace picking up sharply in the later years as interest-on-interest builds.
The figures update instantly as you change any input, so you can compare frequencies and contributions in seconds.
Comparing scenarios
- Switch the frequency to see how monthly compounding beats annual compounding over the same term
- Add a monthly contribution to see how much faster the balance climbs
- Extend the number of years to watch compounding's late-stage acceleration
What you need to get started
Only a modern browser (Chrome, Firefox, Safari, or Edge). There is nothing to install and no account to create.
Verdict
With the Compound Interest Calculator you can see exactly how compounding frequency, contributions, and time shape your final balance — free and private.