Matching principal and interest refers to a repayment method of housing loans (the other is average capital), that is, repaying the same amount of loans (including principal and interest) every month during the repayment period, which is different from average capital.

The calculation formula of monthly repayment amount is as follows:

[loan principal × monthly interest rate ×( 1 monthly interest rate) repayment months ]/[( 1 monthly interest rate) repayment months]

For example:

Suppose that the borrower obtains a personal housing loan of 200,000 yuan from the bank, with a loan term of 20 years and a monthly interest rate of 4.2‰, and repays the principal and interest every month. According to the above formula, the sum of monthly principal and interest payable is 1324.33 yuan.

Extended data:

Average capital:

1. Compound interest is used to calculate loans with equal principal and interest. At the settlement time of each repayment, the interest generated by the remaining principal will be calculated together with the remaining principal (loan balance), that is to say, the outstanding interest will also be calculated, which seems to be more severe than "rolling interest". In foreign countries, it is recognized as a loan method suitable for the interests of lenders.

2. The monthly repayment amount is unchanged, which is essentially that the proportion of principal increases month by month, the proportion of interest decreases month by month, and the number of monthly repayments remains unchanged, that is, in the distribution proportion of "principal and interest" of monthly payment, the proportion of interest paid in the first half is large and the proportion of principal is small. After more than half of the repayment period, it gradually turns into a large proportion of principal and a small proportion of interest.

3. Loans in average capital use a simple interest rate method to calculate interest. At the settlement time of each repayment, only the remaining principal (loan balance) is calculated, that is to say, the outstanding loan interest is not calculated together with the outstanding loan balance, only the principal is calculated.

4. The monthly repayment amount decreases, showing a state of decreasing month by month; It divides the loan principal equally according to the total repayment months, plus the interest of the remaining principal in the previous period, thus forming the monthly repayment amount, so the repayment amount of the average capital method is the largest in the first month, and then decreases month by month, and the less the more.

5. Compared with the two, in the case of the same loan term, amount and interest rate, at the initial stage of repayment, the monthly repayment amount of average capital repayment method is greater than the equal principal and interest. However, according to the whole repayment period, average capital's repayment method will save the expenditure of loan interest.

Baidu Encyclopedia-Equal principal and interest

Two. Calculation formula of equal principal and interest of mortgage loan

Calculation formula of equal principal and interest: monthly repayment amount = loan principal × [monthly interest rate× (1interest rate) repayment months ]{[( 1 interest rate) repayment months ]- 1}. The interest repayment method of mortgage loan with equal principal and interest is to add the total principal and the total amount, and then distribute it evenly to each month of the repayment period. The monthly repayment amount is fixed, but the proportion of principal in the monthly repayment amount increases month by month, and the proportion of interest decreases month by month. Matching principal and interest refers to a loan repayment method, that is, repaying the same amount of loans (including principal and interest) every month during the repayment period. Equal principal and interest and average capital are not the same concept. Although the monthly repayment amount may be lower than that in average capital at the beginning, the interest paid in the end will be higher than that in average capital, which is also a method often used by banks. Compound interest is used to calculate the loan with equal principal and interest in the average capital. At the settlement time of each repayment, the interest generated by the remaining principal will be calculated together with the remaining principal (loan balance), that is to say, the outstanding interest will also be calculated. In foreign countries, it is recognized as a loan method suitable for the interests of lenders. The monthly repayment amount is unchanged, which is essentially that the proportion of principal increases month by month, the proportion of interest decreases month by month, and the number of monthly repayments remains unchanged, that is, in the distribution proportion of "principal and interest" for monthly payment, the proportion of interest paid in the first half of the year is large, and the proportion of principal is small. After more than half of the repayment period, it gradually turns into a large proportion of principal and a small proportion of interest. The average capital loan uses a simple interest rate method to calculate interest. At the settlement time of each repayment, only the remaining principal (loan balance) is calculated, that is to say, the outstanding loan interest is not calculated together with the outstanding loan balance, only the principal is calculated. The monthly repayment amount decreases, showing a state of decreasing month by month; It divides the loan principal equally according to the total repayment months, plus the interest of the remaining principal in the previous period, thus forming the monthly repayment amount, so the repayment amount of the average capital method is the largest in the first month, and then decreases month by month, and the less the more. Compared with the two, in the case of the same loan term, amount and interest rate, at the initial stage of repayment, the monthly repayment amount of average capital repayment method is greater than the equal principal and interest. However, according to the whole repayment period, average capital's repayment method will save the expenditure of loan interest. The advantage of matching principal and interest is that the monthly repayment amount is the same, which is convenient for arranging income and expenditure. Suitable for borrowers whose economic conditions do not allow early repayment and excessive investment, and whose income is relatively stable. The disadvantage is that you need to pay more interest. However, most of the advance payment is interest, and the proportion of principal will increase after half of the repayment period, which is not suitable for early repayment. The advantage of average capital is that the total interest is less than the equal principal and interest. The repayment amount decreases every month, and the later, the easier it is. Moreover, due to the large proportion of principal and small proportion of interest, it is very suitable for early repayment. The disadvantage is that the pressure of prepayment is great, and it needs to have a certain economic foundation and can withstand the pressure of prepayment.

Third, the algorithm of equal principal and interest of mortgage? Please give an example.

Equal principal and interest repayment method: repay the loan principal and interest in equal amount every month, in which the interest decreases month by month and the principal increases month by month.

Suppose the borrower obtains a personal housing loan of 200,000 yuan from the bank, with a loan term of 20 years and an annual interest rate of 4.2%, and pays the principal and interest on a monthly basis. According to the above formula, the monthly repayment of principal and interest is 1233.5438+04 yuan.

Extended data 1, the calculation method is different.

Equal principal and interest repayment method. That is, the borrower repays the loan principal and interest in equal amount every month.

Average capital repayment method. That is, the borrower repays the principal in equal amount every month, and the loan interest decreases month by month with the principal.

2. The total amount of interest paid by the two methods is different.

Under the same loan amount, interest rate and loan life, the total interest of the principal repayment method is less than that of the principal repayment method;

3. The ratio of interest to principal is different in the first few years of repayment.

Interest accounts for a large proportion of the total repayment in previous years (sometimes as high as 90%), while the principal of the principal repayment method is shared equally every time, and the interest is calculated on a daily basis, so the ratio of the two is about 50% at the highest.