All calculators

Finance

Simple Interest Calculator

Work out the interest earned or paid on a principal amount at a fixed rate over time.

—

Formula

Interest equals principal times rate times time, divided by 100.

How it works

Enter the starting amount, the yearly rate, and how many years the money is held. The result shows interest alone plus the total amount. It assumes the rate never changes and no compounding happens.

FAQs

Simple interest differs from compound interest because it is charged only on the original principal, never on interest already earned.

Why is the rate divided by 100?
Percent means per hundred, so 5% is 0.05 in the calculation.

Can I use months instead of years?
Yes — convert months to years first, for example 6 months is 0.5 years.

Are these figures financial advice?
No — they are estimates for planning only, not financial advice. Check with a qualified adviser for decisions involving large sums.

Estimates only, not financial advice. Figures are approximate and do not include all fees, taxes, or changing rates unless stated.

Related calculators

Annuity Payment Calculator

APR Estimate Calculator

Biweekly Mortgage Savings Calculator