Maryland Code, Commercial Law § 12-104

(1) For a period of less than one year, interest is calculated on the premise that there are 360 days in the year and 30 days in each month, which may include the date of the loan and the date due or paid;

(2) Interest on a periodic payment of principal is computed to the due date; or

(3) Except for installment loans made under § 12-103(c) of this subtitle: