The repayment method of paying interest first and then paying principal is called "paying interest first and then paying principal", that is, paying interest first every month and paying off the principal in one lump sum on the last repayment date during the loan period. This repayment method has little repayment pressure in the early stage and great repayment pressure in the last month.

In addition, there are three repayment methods: matching principal and interest, average capital, and paying interest first. Different repayment methods have different repayment pressures and interest to bear, which are suitable for borrowers with different economic conditions and need to be carefully considered before lending.

Interest before principal and equal principal and interest can be calculated in two ways:

1. Interest before principal: the borrower repays the interest on a monthly basis, and the maturity date of the loan is to repay the loan principal in one lump sum. The calculation formula is: interest = principal × annual interest rate × loan term.

2. Matching principal and interest: the borrower pays interest according to a certain principal every month, and the interest generated by the monthly loan is calculated and settled according to the remaining principal at the beginning of the month. The calculation formula is: monthly repayment amount = [principal x monthly interest rate x( 1+ monthly interest rate) loan months ]/[( 1+ monthly interest rate) repayment months-1].