Compound interest calculator: watch your money grow over time

Compound interest means you earn interest on the interest you have already earned, not just on the original amount. Enter a principal, a rate and a duration, and this calculator shows the final amount and how much of it is interest.

The formula is amount = principal x (1 + rate / n) raised to n x years, where n is how many times a year the interest is added. The more often interest compounds, and the longer you leave it, the faster the total grows; the effect is small in the early years and large in the later ones, which is why starting early matters so much.

Frequently asked questions

What is the difference between simple and compound interest?

Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus the interest already added, so it grows faster.

Does compounding frequency matter?

A little. Monthly compounding gives a slightly higher result than yearly at the same rate, but the rate and the duration matter far more.

Where does compounding show up in real products?

In fixed deposits with cumulative payout, recurring deposits, PPF and mutual fund growth, and in the debt on a credit card where it works against you.

Guides · How we rank · About · FAQ · Contact · Editorial policy · Disclaimer · Privacy · Terms

Truely Money is an independent sole proprietorship registered under Udyam (MSME), Udyam Registration No. UDYAM-MP-16-0077048. Questions, corrections or feedback: support@truelymoney.com.