Simple interest calculator
Enter the amount, the yearly rate and the time to see the simple interest and the total.
Interest
How it works
I = P × r × ttotal = P + Iwith r as a decimal per year and t in years (months ÷ 12, days ÷ 365 or 360).
Worked example
- 10,000 × 0.05 × 1.5 years
- = 750 interest
- total 10,750
Frequently asked questions
What is the difference between simple and compound interest?
Simple interest is paid only on the original amount. Compound interest is also paid on interest already earned, so it grows faster over time.
Where is simple interest used?
Short-term loans, some car loans and bonds, treasury bills and many savings accounts that pay out interest instead of adding it to the balance.
How are days counted?
By default a year has 365 days. Some banks use 360 days (the “banker’s year”), which gives slightly more interest; pick it in the list.