There are two methods to calculate the interest of housing loans, namely, the equal principal and interest method and the average capital method. When the interest is calculated by the equal principal and interest method, the interest is equal to the monthly repayment amount multiplied by the number of loan months and then the principal is subtracted; When calculating interest by the average capital method, the interest is equal to the principal multiplied by the monthly interest rate and then multiplied by half of the loan months. Lenders can choose the repayment calculation method according to their own needs.