Free Interest Calculator

Calculate simple or compound interest on any amount.

Simple interest grows linearly — the same dollar amount of interest every period. Compound interest grows on top of previously earned interest, so it accelerates over time. The gap between the two widens the longer your time horizon and the more frequently interest compounds.

Frequently Asked Questions

What's the difference between simple and compound interest?
Simple interest is calculated only on the principal. Compound interest is calculated on principal plus previously earned interest.