Compound Interest Calculator
See how a lump sum grows with any rate and compounding frequency.
Simple Interest Calculator
Work out simple interest and the total amount from a principal, an annual rate and a period in years and months.
Under 10 seconds
Updated 14 Oct 2026
Results
Total amount
₹1,24,000
Principal plus simple interest over 3 years
- Principal
- ₹1,00,000
- Interest earned
- ₹24,000
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</iframe>Simple interest = principal × annual rate × time in years ÷ 100. For example, ₹1,00,000 at 8% for 3 years earns ₹24,000 of interest, so the total is ₹1,24,000. Interest is charged only on the original principal, never on earlier interest.
Visual breakdown
A visual view of your calculation.
Interactive charts arrive here soon.
Smart Insights
Generated from the numbers you entered — no guesswork.
- ₹1,00,000 × 8% × 3 years ÷ 100 = ₹24,000 of interest.
- With compound interest, the same rate would earn more, because interest would also be earned on earlier interest.
What is the Simple Interest Calculator?
What the tool does, who it is for and what it cannot tell you.
Simple interest is interest worked out only on the original principal. It grows by the same amount every year, unlike compound interest, where each year's interest is added to the balance and earns interest itself.
It is used for some short-term loans, certain bonds and many classroom problems. Most bank deposits compound, so use the Compound Interest Calculator for those.
How does the Simple Interest Calculator work?
Each step the calculator runs, in plain language.
- 1
Enter the principal
The amount lent or invested.
- 2
Enter the annual rate
The yearly interest rate in percent; decimals are fine.
- 3
Enter years and months
Months from 0 to 11 are converted to a fraction of a year.
Simple Interest Calculator formula
The exact maths behind every number on this page.
SI = P × R × T ÷ 100; Total amount = P + SI
- P
- Principal — the original amount
- R
- Annual interest rate in %
- T
- Time in years (months ÷ 12 are added to the years)
Simple Interest Calculator calculation example
Hypothetical example: ₹50,000 at 6% a year for 2 years and 6 months.
- 1Time2 + 6 ÷ 12 = 2.5 years
- 2Interest50,000 × 6 × 2.5 ÷ 100 = ₹7,500
- 3Total50,000 + 7,500 = ₹57,500
You would earn ₹7,500 of interest, for a total of ₹57,500.
Important assumptions
What this calculation includes, and what it leaves out.
- Interest is calculated on the original principal only and the rate stays the same for the whole period.
- Months are treated as twelfths of a year; day-count conventions used by some lenders are not applied.
- Taxes and fees are not included.
Financial tips
Practical guidance to act on your result.
- Over long periods, compound interest grows much faster than simple interest at the same rate — compare both before choosing.
- Check whether a lender quotes a simple or a compounded rate; the same number can mean very different costs.
Frequently asked questions
Short, direct answers to the questions we hear most.
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Disclaimer
CalPaisa calculators are for general information and planning only. Results are estimates based on the values you enter and standard formulas, and may differ from the figures your bank, employer, or tax authority applies. Nothing here is investment, tax, or legal advice. Please confirm important decisions with a qualified professional. Read our financial disclaimer, learn how CalPaisa works, or tell us about a calculation you think is wrong.