Compound Interest Calculator

What is compound interest?

Compound interest is interest earned on both your original deposit and on the interest that has already been added to it. Unlike simple interest, which is paid only on the principal, compounding lets your balance grow at an accelerating pace — which is why it is often called the most powerful force in saving and investing.

The formula behind it

The future balance is A = P(1 + r/n)^(nt), where P is the initial amount, r is the annual rate, n is how many times interest is compounded per year and t is the number of years. The more frequently interest compounds — yearly, quarterly, monthly or daily — the faster the balance grows.

How to use this calculator

Enter your initial amount, the annual interest rate, the number of years and how often interest compounds, then press Calculate. You will see the final balance and the total interest earned, so you can compare savings accounts or project long-term growth.

Making compounding work for you

Time is the biggest lever: the earlier you start, the more the exponential effect rewards you. Adding regular contributions and choosing accounts that compound more often both boost the final result. Even a modest rate can turn small, consistent deposits into a substantial sum over decades.