Compound Interest Calculator
See how an investment grows over time with compound interest and optional monthly contributions. Enter the numbers to get your final balance, how much you put in, and how much is pure interest.
How to use
Enter your initial amount, annual interest rate, number of years and how often interest compounds (annually, quarterly, monthly or daily). Add a monthly contribution if you save regularly.
The result splits your final balance into total invested vs. interest earned, so you can see the power of compounding. Try a longer term or higher rate to see how much difference they make.
FAQ
What is compound interest?
Interest calculated on both your original amount and the interest already added, so your balance grows faster over time — 'interest on interest'.
How does compounding frequency change the result?
More frequent compounding (daily vs. annually) earns slightly more, because interest is added and starts earning sooner. The effect grows with the rate and the term.
Does it include regular contributions?
Yes — add a monthly contribution and it's added every month and compounded with the rest, which is how most savings and retirement accounts actually grow.
Is this financial advice?
No, it's a math tool for illustration. Real returns vary and it doesn't account for tax, inflation or fees. Use it to compare scenarios, not as a guarantee.