The principle of calculating the days of loan interest is to calculate 30 days per month instead of counting the end. Divide the annual interest rate by 360 to convert it into a daily interest rate, instead of dividing it by the actual number of days 365 or 366.

Because the interest rate conversion is only 360 days a year, the actual daily interest rate will be calculated as 365 days a year, and the result will be slightly different. Which formula is used specifically, the central bank gives financial institutions the right to choose independently. Therefore, the parties and financial institutions can agree on this in the contract.