The Annual Percentage Rate (APR) is a method to compute annualised credit cost, which includes interest rate and loan origination charges. The APR calculator does not include charges like stamp duty, prepayment charges, CERSAI charges etc.
The online APR calculator tool calculates the percentage by using a formula, Annual Percentage Rate (APR) = (Periodic Interest Rate x 365 Days) x 100
Once you filled in all the necessary details, you will be provided the APR.