Calculate simple interest for loans, investments, or savings over time
Learn how to use the Interest Cost Calculator and understand simple interest calculations
Simple interest is calculated only on the principal amount, or on the portion of the principal amount that remains unpaid. The formula for calculating simple interest is:
Simple Interest = Principal × Rate × Time
This calculator shows both the interest amount earned or paid, as well as the total amount after interest is added to the principal.
Note: This calculator uses simple interest calculation. For compound interest calculations, where interest is earned on both the principal and accumulated interest, please use our Compound Interest Calculator.