Simple Interest Calculator

Compute simple interest and maturity value for a principal over time.

Simple Interest Calculator helps you compute simple interest and maturity value for a principal over time. Enter amount (principal), annual rate, and time, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Simple Interest calculator does Simple Interest Calculator is built for money decisions — loans, savings, payments, and taxes. Compute simple interest and maturity value for a principal over time. You enter amount (principal), annual rate, and time, then Simple Calculators computes the result instantly. Rates, fees, and tax rules vary by lender and country, so treat results as planning numbers, not a contract. How the math works Enter the Amount (principal), the Annual rate and the Time in years (decimals are fine, so 6 months is 0.5). Interest = principal × annual rate × years, and the amount at the end is principal + interest. Interest is never added to the balance to earn more interest; for that, use a compound interest calculator. The formula: I = P × r × t. P is the principal, r the yearly interest rate and t the time in years.