Va. Code § 53.1-116
Unless he is serving a mandatory minimum sentence of confinement, each prisoner sentenced to 12 months or less for a misdemeanor or any combination of misdemeanors shall earn good conduct credit at the rate of one day for each one day served, including all days served while confined in jail prior to conviction and sentencing, in which the prisoner has not violated the written rules and regulations of the jail.
Prisoners eligible for parole under § 53.1-151, 53.1-152 or 53.1-153 shall earn good conduct credit at a rate of 15 days for each 30 days served with satisfactory conduct.
The jailer may grant the prisoner additional credits for performance of institutional work assignments, participation in classes, or participation in local work force programs, if available at the facility, at the rate of five days for every 30 days served. The time so deducted shall be allowed to each prisoner for such time as he is confined in jail. It shall be the responsibility of the jailer in each facility to determine the manner in which these additional credits may be awarded and to include this information in the written policy mandated by clause (iii) of this subsection.
For each violation of the rules prescribed herein, the time so deducted shall be added until it equals the full sentence imposed upon the prisoner by the court.
However, any prisoner committed to jail upon a felony offense committed on or after January 1, 1995, shall not earn good conduct credit, sentence credit, earned sentence credit, other credit, or a combination of any credits in excess of that permissible under Article 4 (§ 53.1-202.2 et seq.) of Chapter 6 of this title. So much of an order of any court contrary to the provisions of this section shall be deemed null and void.
Va. Code § 53.1-116