The ending balance method uses your beginning balance minus payments plus charges made during the billing cycle. The number of days in the billing cycle doesn't affect the amount of the finance charge.
The previous balance method uses the balance at the beginning of the billing cycle which is also the ending balance of the last billing cycle. No payments or charges are included. The number of days in the billing cycle doesn't affect the amount of the finance charge.
How it's calculated: The bill will show beginning balance and ending balance for your account. The finance charge is based on the outstanding balance at the beginning of the billing cycle