Free simple and compound interest calculator
Work out the interest on a loan, a deposit or an investment, and compare simple interest with compound interest side by side. Enter the amount, the yearly rate and the time, and see the interest, the total amount and a year-by-year table. For compound interest you can choose how often the interest is added: yearly, half-yearly, quarterly, monthly or daily.
How to use the interest calculator
- Choose Simple interest or Compound interest.
- Enter the amount (the principal) in rupees.
- Enter the annual interest rate in percent.
- Enter the time in years and months.
- For compound interest, pick how often the interest is compounded.
- Click Calculate.
The formulas
Simple interest is SI = P × r × t ÷ 100, where P is the principal, r is the annual rate in percent and t is the time in years. The total is P + SI. Compound interest gives A = P × (1 + r ÷ (100 × n))n × t, where n is the number of times the interest is compounded each year. The compound interest is A − P.
Worked example
On ₹1,00,000 at 8% a year for 3 years, simple interest is ₹24,000 and the total is ₹1,24,000. With compound interest added yearly, the total is about ₹1,25,971, so the interest is about ₹25,971. Compounded quarterly it is about ₹1,26,824, and compounded monthly about ₹1,27,024. Compound interest earns more because each period's interest also earns interest.
Simple or compound: which applies to you
- Simple interest is common on some short personal loans and informal lending, and on the interest part of many school and textbook problems.
- Compound interest is common on bank deposits, savings, and most investments.
- Always check the terms of your own loan or deposit. Lenders may use other methods, such as reducing balance on loans. For loan instalments, use the EMI calculator.
Runs entirely in your browser
The calculation happens on your device. Nothing you type is sent to our servers. If you are comparing deposits, also try the FD calculator, or use the percentage calculator for quick percentage maths.
Important notice
This is an estimate for planning and learning. It is not financial advice, and your lender or bank may calculate interest differently, for example by counting actual days. Confirm the figures with them before you decide. SR Infobiz accepts no liability for decisions made only on the basis of this tool.
Need a custom calculator or tool built for your business? Get in touch with SR Infobiz.