if the annual interest rate is 14.4%, the calculation method of interest is to multiply the loan principal with the annual interest rate. Assuming that the principal of the loan is 1, yuan, the interest can be calculated by the following formula: interest = loan principal × annual interest rate, interest = 1, yuan× 14.4% = 1,44 yuan. So, if the annual interest rate is 14.4% and the loan principal is 1, yuan, the interest you need to pay is 1,44 yuan. Interest rate, the abbreviation of "interest rate", refers to the ratio of interest amount to deposit principal or loan principal within a certain period. Usually divided into annual interest rate, monthly interest rate and daily interest rate. The annual interest rate is expressed as a percentage of the principal, and the monthly interest rate is expressed as a few thousandths.