Simple Interest Calculator
Calculate simple interest and total value from principal, annual rate and time.
Set your values
Adjust the values, then calculate your result.
How to use Simple Interest Calculator
- Enter the measurements or amounts in the fields above.
- Check that dimensions, rates and units match the labels.
- Select “Calculate simple interest” to see a clear estimate and the formula used.
How the simple interest calculator works
Simple interest = principal × annual rate × time. Total = principal + interest; compounding is not included.
Check your measurements and assumptions
Use the rate and time basis from your agreement. This estimate excludes fees, taxes, compounding and changing balances and is not a loan or investment quote.
Review the estimate before you act
Compare this result with an independent measurement, supplier quote or institution guidance when the decision matters. Confirm that the units and assumptions match the labels above, and update the inputs when the conditions change. Keep a note of the values used so you can reproduce the estimate later. This calculator is a planning aid and does not replace professional, product-specific or local guidance.
What is the formula for simple interest?
Multiply the principal by the annual rate as a decimal and by the number of years.
Is input uploaded?
Processing takes place in your browser. This tool does not send your input or selected files to a conversion API.