Md. Code Ann., Corr. Servs. § 3-704

(a) An inmate shall be allowed a deduction in advance from the inmate’s term of confinement.

(b) (1) The deduction allowed under subsection (a) of this section shall be calculated: (i) from the first day of commitment to the custody of the Commissioner through the last day of the inmate’s term of confinement; (ii) except as provided in paragraph (2) of this subsection, at the rate of 10 days for each calendar month; and (iii) on a prorated basis for any portion of a calendar month. (2) If an inmate’s term of confinement includes a consecutive or concurrent sentence for a crime of violence as defined in § 14–101 of the Criminal Law Article or a crime of manufacturing, distributing, dispensing, or possessing a controlled dangerous substance in violation of § 5–612 or § 5–613 of the Criminal Law Article, the deduction described in subsection (a) of this section shall be calculated at the rate of 5 days for each calendar month.

(c) A deduction under this section may not be allowed for a period during which an inmate does not receive credit for service of the inmate’s term of confinement, including a period: (1) during which the inmate’s sentence is stayed; (2) during which the inmate is not in the custody of the Commissioner because of escape; or (3) for which the Maryland Parole Commission has declined to grant credit after revocation of parole or mandatory supervision.