Simple Interest Calculator
Interest that never compounds: principal × rate × time, with the total spelled out. It runs entirely in your browser — nothing you type is uploaded anywhere.
Your figures
Result
How this calculator works
Simple interest is charged only on the original principal, for the whole term. Enter the principal, the annual rate and the time (years plus any extra months) and the calculator returns the interest, the total amount and the interest earned per year — a flat figure, because under simple interest every year earns exactly the same as the first.
That flatness is the point of the method and the reason it survives in short-term lending, some bonds' coupon arithmetic, late-payment clauses and classroom finance: anyone can verify it with one multiplication. It is also why simple interest flatters a borrower and short-changes a saver over long periods — the interest itself never goes to work.
Good practice and limits
When a quote says “6%”, ask which method stands behind it before comparing it with anything. Over one year the two methods agree almost exactly; over ten, the compound figure pulls away. For a fair comparison, convert both offers to the total amount payable or receivable over the same term — totals cannot be spun the way rates can.