Free Simple & Compound Interest Calculator
Enter the principal, the yearly rate and the time. You see simple interest and compound interest side by side, so you can see how much compounding adds.
Note: Results are estimates for learning and planning. They are not financial, tax or investment advice, and actual figures from your bank or lender may differ. See our disclaimer.
How to use Simple & Compound Interest Calculator
- Enter the principal amount.
- Enter the interest rate per year.
- Enter the time in years and extra months.
- Choose how often interest is compounded, then click Calculate interest.
About this tool
Simple interest = P × R × T ÷ 100, and it is always charged on the original amount. Compound interest = P × (1 + R ÷ (100 × n))^(n × T) − P, where n is how many times a year interest is added, so interest is earned on earlier interest as well. For example, ₹1,00,000 at 8% for 5 years gives ₹40,000 simple interest and about ₹46,933 compound interest with yearly compounding. The longer the time and the higher the rate, the bigger the gap.
Frequently asked questions
What is the difference between simple and compound interest?
Simple interest is charged only on the original amount. Compound interest is charged on the amount plus the interest already added.
Which one do loans use?
Most bank loans and deposits use compounding in some form. Check your agreement.
What does compounding frequency mean?
How often interest is added to the balance, such as yearly or quarterly. More frequent compounding gives slightly more interest.
Can I use months?
Yes. Enter extra months along with the years.
Is my data stored?
No. Everything runs in your browser.