1. There are two simplest algorithms for monthly mortgage payments, namely the two repayment methods: equal principal repayment and equal principal and interest repayment.

(1) Equal-amount principal repayment algorithm: monthly payment = (loan principal/number of loan periods) + (loan principal - principal repaid) * monthly interest rate.

(2) Equal principal and interest repayment algorithm: monthly monthly payment = {borrowing principal × monthly interest rate × (1 + monthly interest rate) ^ number of loan periods} ÷ [(1 + monthly interest rate) ^ borrowing Issue number-1].

2. The monthly mortgage payment is closely related to the mortgage interest rate. The mortgage interest rate refers to a loan obtained from a bank using real estate. The interest on the loan must be paid according to the interest rate specified by the bank. China's mortgage interest rates are uniformly stipulated by the People's Bank of China, and each commercial bank can float within a certain range when implementing it. China's mortgage interest rates are not always constant, but change frequently. The form is that the interest rates have been rising, so the situation before the interest rate increase is often compared with the situation after the interest rate increase.

The monthly loan payment is related to the down payment amount, loan term, loan repayment method, and bank interest rate. The loan interest for equal principal and interest repayments and equal principal repayments is calculated as follows:

1. Equal principal and interest repayments

Monthly payment amount = [loan principal × monthly interest rate × (1＋monthly interest rate)＾number of repayment months〕÷〔(1＋monthly interest rate)＾number of repayment months-1〕

Monthly interest payable = loan principal × monthly interest rate × [(1+ Monthly interest rate)^Number of repayment months-(1+monthly interest rate)^(Repayment month serial number-1)〕÷[(1+monthly interest rate)^Number of repayment months-1]

Every month Principal repayable = loan principal × monthly interest rate × (1 + monthly interest rate) ^ (repayment month number - 1) ÷ [(1 + monthly interest rate) ^ number of repayment months - 1]

Total interest = number of repayment months Number of months of repayment) + (loan principal - cumulative amount of repaid principal) × monthly interest rate

Monthly principal repayment = loan principal ÷ number of repayment months

Every month Monthly interest repayment = remaining principal × monthly interest rate = (loan principal - cumulative amount of repaid principal) × monthly interest rate

Monthly monthly payment reduction amount = monthly principal repayment × monthly interest rate = Loan principal ÷ Number of repayment months × Monthly interest rate

Total interest = [(Total loan amount ÷ Number of repayment months + Total loan amount × Monthly interest rate) + Total loan amount ÷ Number of repayment months × (1+monthly interest rate)〕÷2×number of repayment months-total loan amount

Monthly interest rate = annual interest rate÷12.

In addition to calculating by yourself according to the calculation formula, you can also find the corresponding loan calculator to calculate.