Simple interest calculator
Work out interest the straightforward way. Enter the principal, rate and time to get the interest and the total amount using the classic P × r × t formula.
Details
Tweak the numbers - results update live
₹1L
Principal
amount invested
₹50K
Interest
earned
1.50×
Growth
value ÷ principal
How it grows
Principal vs total value, year by year
Principal vs interest
What you put in vs what it earns
- Principal₹1L
- Interest₹50K
Total value
₹1,50,000
Straightforward
Flat interest, easy to predict
Simple interest charges the same amount every year because it’s always a percentage of the original principal. No compounding, no surprises - useful for short-term loans and quick estimates.
Interest = P × r × t ÷ 100
- 1
Take the principal
P is the amount borrowed or invested.
- 2
Apply the flat rate
r% of the principal is charged each year - always the same.
- 3
Multiply by time
Over t years the interest is simply that yearly amount times t.
- 4
Add to principal
The total amount is principal plus the simple interest.
Questions
Frequently asked
Simple interest is interest calculated only on the original principal, not on any interest already earned. It stays the same every year, which makes it easy to predict. It is common in short-term loans, some vehicle and personal loans, and fixed-term arrangements where interest is not reinvested.
Simple interest = P × r × t ÷ 100, where P is the principal, r is the annual rate in percent, and t is the time in years. So ₹1,00,000 at 10% for 5 years earns ₹50,000 of interest, for a total of ₹1,50,000. The interest is the same ₹10,000 each year.
Simple interest is charged only on the principal, so it grows linearly. Compound interest is charged on the principal plus accumulated interest, so it grows faster over time. For the same principal, rate and period, compound interest always yields more - compare with our compound interest calculator.
Simple interest commonly applies to short-tenure personal and vehicle loans, certain gold loans, and some fixed deposits where interest is paid out periodically rather than reinvested. Many informal and short-term lending arrangements also use simple interest.
Yes. The maturity or total amount is simply the principal plus the simple interest earned: A = P + (P × r × t ÷ 100). The calculator shows both the interest component and the total so you can see exactly what you’ll receive or repay.