How to use the Simple Interest Calculator
- Fill in Principal, Interest rate and Time. Type a number or drag the slider.
- The result appears straight away and changes as you type. There is no button to press.
- Use the worked example, table and formula below to check the result or compare other values.
Worked example
Simple interest on ₹1 lakh at 10% a year for 2 years is ₹20,000, so the total amount is ₹1,20,000.
Quick answers
- What does ₹1 lakh become at 5% simple interest in 5 years?₹1 lakh at 5% a year simple interest becomes ₹1,25,000 in 5 years.
- What does ₹1 lakh become at 8% simple interest in 5 years?₹1 lakh at 8% a year simple interest becomes ₹1,40,000 in 5 years.
- What does ₹1 lakh become at 10% simple interest in 5 years?₹1 lakh at 10% a year simple interest becomes ₹1,50,000 in 5 years.
- What does ₹1 lakh become at 12% simple interest in 5 years?₹1 lakh at 12% a year simple interest becomes ₹1,60,000 in 5 years.
- What does ₹1 lakh become at 15% simple interest in 5 years?₹1 lakh at 15% a year simple interest becomes ₹1,75,000 in 5 years.
Simple interest table for ₹1 lakh
Total amount (principal plus simple interest) on ₹1 lakh.
| Interest rate | 1 year | 2 years | 3 years | 5 years | 10 years |
|---|---|---|---|---|---|
| 5% | ₹1,05,000 | ₹1,10,000 | ₹1,15,000 | ₹1,25,000 | ₹1,50,000 |
| 8% | ₹1,08,000 | ₹1,16,000 | ₹1,24,000 | ₹1,40,000 | ₹1,80,000 |
| 10% | ₹1,10,000 | ₹1,20,000 | ₹1,30,000 | ₹1,50,000 | ₹2,00,000 |
| 12% | ₹1,12,000 | ₹1,24,000 | ₹1,36,000 | ₹1,60,000 | ₹2,20,000 |
| 15% | ₹1,15,000 | ₹1,30,000 | ₹1,45,000 | ₹1,75,000 | ₹2,50,000 |
How it is calculated
SI = P × R × T ÷ 100
P is the principal, R is the yearly rate in percent and T is the time in years. With simple interest you earn or pay interest only on the original principal, so the interest is the same every year.
Good to know
- For periods in months, divide the months by 12 and enter the result as years.
- Simple interest is common in short informal loans. Banks mostly use compound or reducing-balance interest.
- Compare with the compound interest calculator to see how much more compounding adds.
Common questions
Simple interest vs compound interest?
Simple interest is charged only on the principal. Compound interest is charged on the principal plus the interest already added, so it grows faster over time.
How do I enter months?
Convert months to years. For example, 6 months is 0.5 years and 18 months is 1.5 years.
How do I find the rate if I know the interest?
Rate = interest × 100 ÷ (principal × time in years).
Where is simple interest used?
In some short-term loans, bills and school maths problems. Deposits and most bank loans use other methods.
Formula and text last reviewed in October 2026. Results are estimates, not financial advice.