Compound Interest Calculator
Enter a starting amount, interest rate and time to see how compounding grows your money — add a monthly contribution to supercharge it.
About compound interest
Albert Einstein reportedly called compound interest “the eighth wonder of the world.” The earlier you start and the longer you leave money invested, the more powerful it becomes, because you earn interest on your interest. This calculator shows that growth clearly, with or without regular monthly deposits.
Frequently asked questions
What is compound interest?
Compound interest is interest earned on both your original money and the interest it has already earned. Over time this “interest on interest” can grow your savings dramatically.
What does compounding frequency mean?
It’s how often interest is added — yearly, monthly or daily. More frequent compounding grows money slightly faster.
Can I include regular deposits?
Yes. Add a monthly contribution and the calculator includes those deposits and the interest they earn.
Related tools
Try the Investment Calculator or Inflation Calculator.