Simple Interest Calculator
Calculate simple interest on a principal with any rate and time, in years and months.
Last updated: August 2026
Total interest
₹6,000
End balance
₹26,000
Monthly interest
₹50
Over 120 months
Simple interest = principal × rate × time. Interest is only ever charged on the original principal — no compounding. Most savings accounts and credit cards compound instead; use the compound interest calculator for those.
How it works
Interest = P × r × t, where t is in years (months ÷ 12). End balance = P + interest.
Example: ₹20,000 at 3% for 10 years → ₹6,000 interest, ₹26,000 total.
Frequently Asked Questions
What is the simple interest formula?
Simple interest = principal × rate × time, where the rate is the annual rate as a decimal and time is in years. For ₹20,000 at 3% for 10 years: 20000 × 0.03 × 10 = ₹6,000 interest, ending at ₹26,000.
When is simple interest used in India?
Simple interest is standard for very short-term fixed deposits (under ~90 days), many small savings schemes, loan defaults and penal interest. Longer savings products almost always compound.
What is the difference between simple and compound interest?
Simple interest is charged only on the original principal, so it grows linearly. Compound interest also earns interest on accumulated interest, so the balance grows faster over time — switch to the compound interest calculator to compare.
How do I calculate simple interest for months?
Convert the months into years by dividing by 12, then use the formula. The calculator does this automatically when you enter extra months.