(a) Good conduct time applies only to eligibility for parole or mandatory supervision as provided by Section 508.145 or 508.147 and does not otherwise affect an inmate’s term. Good conduct time is a privilege and not a right. Regardless of the classification of an inmate, the department may grant good conduct time to the inmate only if the department finds that the inmate is actively engaged in an agricultural, vocational, or educational endeavor, in an industrial program or other work program, or in a treatment program, unless the department finds that the inmate is not capable of participating in such a program or endeavor.
(b) An inmate accrues good conduct time according to the inmate’s classification in amounts as follows:
(1) 20 days for each 30 days actually served while the inmate is classified as a trusty, except that the department may award the inmate not more than 10 extra days for each 30 days actually served;
(2) 20 days for each 30 days actually served while the inmate is classified as a Class I inmate; and
(3) 10 days for each 30 days actually served while the inmate is classified as a Class II inmate.

(c) An inmate may not accrue good conduct time during any period the inmate is classified as a Class III inmate or is on parole or under mandatory supervision.
(d) An inmate may accrue good conduct time, in an amount determined by the department that does not exceed 15 days for each 30 days actually served, for diligent participation in an industrial program or other work program or for participation in an agricultural, educational, or vocational program provided to inmates by the department. For the purposes of this subsection, the term “participation in an educational program” includes the participation of the inmate as a tutor or a pupil in a literacy program authorized by Section 501.005. The department may not award good conduct time under this subsection for participation in a literacy program unless the department determines that the inmate participated in good faith and with diligence as a tutor or pupil.
(e) If a person is confined in a county jail, the department shall award good conduct time to the person up to an amount equal to the amount earned by an inmate in the entry level time earning class. The department shall award good conduct time to a defendant for diligent participation in a voluntary work program operated by a sheriff under Article 43.101, Code of Criminal Procedure, in the same manner as if the inmate had diligently participated in an industrial program or other work program provided to inmates by the department. The sheriff of each county shall have attached a certification of the number of days each inmate diligently participated in the volunteer work program operated by the sheriff under Article 43.101, Code of Criminal Procedure.
(f) Repealed by Acts 1999, 76th Leg., ch. 1188, Sec. 1.37(b), eff. Sept. 1, 1999.