Simple Interest Calculator
Find simple interest and the ending balance from the principal, rate and time.
Change the values and press Calculate to work out your own figures.
Enter the principal, rate and time.
Show the working
- interest = principal × rate × years
How to use it
Enter the principal, rate and time.
Enter amounts without commas or with them; rates are percentages (5 for 5%). Negative amounts are allowed where a sign means money paid out.
Key facts
interest = principal × rate × time; balance = principal + interest
Questions
What is simple interest on $20,000 at 3% for 10 years?
$6,000, for $26,000.
Formulas
interest = principal × rate × time; balance = principal + interest
Sources
Limitations
- Results are estimates for planning, not offers or financial advice; lenders and banks may round, count days or time payments differently.
- Rates are nominal annual rates compounded as you choose; payments at a different frequency use the equivalent periodic rate.