What formula does simple interest use?

Simple interest equals principal multiplied by annual rate multiplied by time, divided by 100.

When should I use compound interest instead?

Use compound interest when interest is periodically added to the balance and then earns interest itself.

FREE SIMPLE INTEREST CALCULATOR

Use the standard simple-interest formula for clear school, business, and savings examples.

INPUTS

PrincipalAnnual rate (%)Time (years)

interest = principal × annual rate × years ÷ 100

ABOUT THIS TOOL

Use principal, annual rate, and years to calculate simple interest and final amount in a clear result panel.

KEY FUNCTIONS

Principal, rate, and time inputsInterest earnedTotal maturity amount

LEARN THE METHOD

KEEP SOLVING

Project compound growth using a starting balance, annual rate, years, frequency, and optional regular contributions.

Estimate an amortized payment, total repayment, and interest for a loan using a chosen payment frequency.

Choose from ten percentage workflows including change, reverse calculations, selling-price markup, profit margin, and compound growth.