Usually, if a customer is late paying the balance, finance charges will
be calculated and the grace period does not apply. Finance charges
incurred depend on the grace period and balance; with most credit cards
there is no grace period if there is any outstanding balance from the
previous billing cycle or statement (i.e. interest is applied on both
the previous balance and new transactions). However, there are some
credit cards that will only apply finance charge on the previous or old
balance, excluding new transactions.