A billing cycle is the time between the last statement closing date and the next and typically last anywhere from 28 to 31 days, depending on the card issuer. The amount of days in your billing cycle may fluctuate month to month since the number of days in each month varies, but there are regulations to ensure that they are as “equal” as possible.
Credit card companies use the billing cycle to calculate your interest accrual and more importantly the minimum due per period. Your due date is required to remain the same every billing cycle and your due date must be at least 21 days from the end of a billing cycle, giving you time to budget your payments.
The period of time between the end of a billing cycle and when your bill is due is called your grace period, and if you pay your balance off within this time, you won’t incur interest.