Interest Earned Calculator

About this calculator

Simple interest is calculated with the formula I = P × r × t, where P is the principal deposited, r is the annual interest rate, and t is the number of years — unlike compound interest, the interest earned in each period is always based on the original principal alone, never on interest already earned.

This makes simple interest straightforward to project for products like certain certificates of deposit, short-term promissory notes, or bonds that pay a fixed coupon on face value rather than compounding. Entering the principal, annual rate, and number of years shows the total interest earned over the full term, useful for comparing a simple-interest product against a compounding one over the same period.