How to use the Simple Interest Calculator
- Enter the principal amount.
- Enter the yearly interest rate.
- Enter the time in years (use 0.5 for six months).
- Read the interest and the total amount.
How it's calculated
Show the formula
Simple interest = P × R × T ÷ 100
P = principal · R = rate per year · T = time in years
P = principal · R = rate per year · T = time in years
Worked example
These are the example numbers the calculator opens with. Change any of them above to see your own result.
You enter
| Principal | Rs 5,00,000 |
|---|---|
| Rate (per year) | 10% |
| Time | 3 years |
You get
| Interest | Rs 1,50,000 |
|---|---|
| Principal | Rs 5,00,000 |
| Total amount | Rs 6,50,000 |
Tips
- Simple interest is charged only on the original amount, so it grows slower than compound interest.
- For months, divide by 12: 9 months = 0.75 years.
Frequently asked questions
What is the difference between simple and compound interest?
Simple interest is only on the original amount. Compound interest is also charged on interest already added, so it grows faster over time.
Where is simple interest used?
Some short-term loans, certain deposits that pay out profit regularly, and many school and exam questions use simple interest.
How do I find the rate if I know the interest?
Rate = interest × 100 ÷ (principal × time). Try different rates here until the interest matches.