Simple Interest Calculator (2026)

This is your starting balance before interest. For loans, it’s the amount you borrow; for investments, it’s the amount you deposit. Results scale linearly with this value in simple interest.

Enter the nominal yearly rate (e.g., 5 for 5%). In simple interest, the rate does not compound; the same interest accrues each period.

Total duration of the investment or loan in years. Simple interest scales directly with time: doubling time doubles the interest.