1. Calculation formula of interest: principal × annual interest rate (percentage) × deposit period.

2. Equal principal and interest method:

Calculation formula: monthly repayment amount = monthly interest rate of principal [(65438+ 10 interest rate) n/[(65438+ 10 interest rate) n- 1]

Where n represents the number of months of loan, and n represents the power of n, such as 240, representing the power of 240 (20 years and 240 months of loan).

Monthly interest rate = annual interest rate/12

Total interest = monthly repayment amount-loan months-principal

3, the law of average capital:

Calculation formula: monthly repayment amount = principal /n monthly interest rate of remaining principal.

Total interest = monthly interest rate of principal (loan months /20.5)

4. Loan interest is generally divided into annual interest rate, monthly interest rate and daily interest rate.

5. The interest rate is expressed as a percentage, the monthly interest rate is expressed as one thousandth, and the daily interest rate is expressed as one thousandth.

6. Annual interest rate ÷ 12= monthly interest rate; Monthly interest rate ÷30= daily interest rate; Annual interest rate ÷360= daily interest rate.

Extended data:

Classification situation

The interest calculation formula is mainly divided into the following four situations:

First, the basic formula for calculating interest. The basic formula for calculating the interest of savings deposits is: interest = principal × deposit period × interest rate;

The second is the conversion of interest rate, in which the conversion relationship among annual interest rate, monthly interest rate and daily interest rate is: annual interest rate = monthly interest rate × 12 (month) = daily interest rate ×360 (day); Monthly interest rate = annual interest rate ÷ 12 (month) = daily interest rate ×30 (days); Daily interest rate = annual interest rate ÷360 (days) = monthly interest rate ÷30 (days). In addition, the use of interest rates should be consistent with the deposit term;

Third, the starting point of the interest calculation formula.

1, the starting point of savings deposit interest is RMB, and interest is not paid for cents below RMB;

2. The interest amount shall be calculated to one decimal place and rounded to one decimal place when actually paid;

3. Except for current savings, which are settled on an annual basis and interest can be converted into principal, all other savings deposits, regardless of the duration, are paid with the principal at the time of withdrawal, excluding compound interest;

Fourth, the calculation of the deposit period in the interest calculation formula.

1, and the storage period is calculated by counting the first number and the last number;

2, regardless of the big month, small month, flat month, leap month, every month is calculated as 30 days, and the whole year is calculated as 360 days;

3. The maturity date of all kinds of deposits shall be calculated on an annual and monthly basis. If the account opening date is the missing date of the expiration month, the expiration date should be the last day of the expiration month.

Provisions for calculating the term of deposit:

1. When calculating interest, the number of days of deposit is calculated at the beginning, not at the end, that is, from the date of deposit to the day before withdrawal;

2, regardless of leap year, average year, regardless of the size of the month, 360 days a year, 30 days a month;

3. Calculated by year, month and day, the maturity date of various time deposits shall be subject to year, month and day. That is, from the deposit date to the same day of the following year is a pair of years, and the deposit date to the same day of next month is a pair of months;

4. Maturity date of time deposit. For example, if you don't work on legal holidays, you can withdraw one day in advance and calculate interest at maturity. The procedure is the same as that of early withdrawal.

The calculation formula of interest: principal × annual interest rate (percentage) × deposit period.

If the interest tax is X (1-5%)

Total principal and interest = principal interest

The calculation formula of accrued interest is: accrued interest = principal × interest rate × time.

Accrued interest shall be accurate to two decimal places, and the number of interest-bearing days shall be calculated according to the actual holding days.

PS: The deposit period should correspond to the interest rate, not necessarily the annual interest rate, but also the daily interest rate and the monthly interest rate.