Calculate the effective rate of interest from investment amounts
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Results are estimates, not financial advice. Rates, charges and rules change, so confirm with your bank, post office or a financial adviser before you decide. Terms of use
How to Use
- Enter the Investment / loan amount, meaning the money you put in or lent.
- Enter the Maturity / future value you got back at the end.
- Enter the Duration in years.
- The effective annual rate of return shows up as you type, along with the total gain. Use copy result or pdf to keep a copy.
When do you need this calculator?
Use this rate of interest calculator when you know what you put in and what you got back, and want the effective annual rate of return (CAGR). People use it to compare chit funds, check what a post office scheme really pays, or test an agent's claim that "your money will double".
The CAGR formula
Here n is the number of years. Multiply the result by 100 to get the rate as a percentage per year. For example, if ₹1 lakh grows to ₹2 lakh in 10 years, the CAGR is 21/10 − 1, or about 7.18% a year.
Flat rate vs reducing balance rate
A loan advertised at a "flat 10%" actually costs around 18–20% on a reducing balance. Convert flat rates to their reducing-balance equivalent before you compare loan offers. This calculator helps you check the true rate on any investment or loan.