<prompt> Human: For example Ill use nice round numbers to make it easier.Credit card interest rate is 10I have 2,000 in chargers that are due on March 1.I pay 1000 on Feb 15.I pay 500 on March 1.Remaining balance being 500.I would think I would get charged interest for the 500 I didnt pay off, but based on the interest charges fee, thats incorrect, so I was reading the mumbo jumbo and it didnt make much since.So...help...me understand o.O  <response>: Interest charges are calculated on a monthly basis. Since months vary in length, most credit card issuers use a Daily Periodic Rate DPR to calculate interest charges. The DPR is calculated by dividing the APR by 365. That number is then multiplied by the average daily account balance more on that in a moment and by the number of days in the statement billing cycle. Heres the basic formula used to calculate your monthly interest rate:Balance x DPR x days in statement billing cycle interest for that months statement 