Assuming the principal is 100 yuan and the monthly interest rate is 1%, the calculation is as follows:100 *1%/30 * 30 =1yuan.
For example:
1. If the monthly interest rate is 1%, for example, the loan or deposit of a month 1 day is 100 yuan; Then the interest for the next month 1 day is 65438+ one year 12 months' total interest in 0 yuan, which is 12 yuan. If it is less than one month, the interest for the remaining days shall be calculated according to the current interest listed by the bank on the same day. This is a simple and interesting algorithm;
2. Compound interest is more complicated to calculate. You need to add up the interest and principal after each month as the principal of next month to calculate the interest of next month. Or take 100 yuan as an example to calculate compound interest. The interest in the first month is 1 yuan principal and interest * * 1 kloc-0/yuan, and the interest in the second month is 1.0 1 principal and interest * *1yuan, and so on.
The monthly interest rate is the monthly interest. The monthly interest rate is expressed as a few thousandths of the principal. One ten thousandth is the dividend, that is, 1% is 1.
Extended data
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.
Refer to Baidu Encyclopedia-interest calculation formula