Michigan’s good time law, codified at MCL 800.33, still exists, but it only applies to prisoners whose crimes were committed before April 1, 1987. Offenses committed between April 1, 1987 and the Truth in Sentencing cutoffs in 1998 and 2000 earn a smaller “disciplinary credit” instead. Almost everyone sentenced for a crime committed after December 2000 earns no credit at all and must serve the full minimum sentence before the parole board can consider release.
Which System Applies to a Sentence
Three dates decide which regime a prisoner falls under, and they turn on the date of the offense, not the date of sentencing or incarceration.
- Crimes committed before April 1, 1987: traditional good time credits under MCL 800.33, with the escalating monthly rate below.
- Crimes committed on or after April 1, 1987 but before the Truth in Sentencing cutoff: disciplinary credits at a flat rate.
- Assaultive crimes committed on or after December 15, 1998, and all other crimes committed on or after December 15, 2000: Truth in Sentencing. No good time, no disciplinary credits, no corrections center placement.1State of Michigan: Department of Corrections. Truth in Sentencing Information
Older cutoffs from 1978’s Proposal B further limit good time for certain serious offenses even within the pre-1987 window, and a separate rule bars good time for certain controlled substance offenses committed on or after September 1, 1978.
Good Time Credits for Pre-1987 Offenses
A prisoner serving a sentence for a crime committed before April 1, 1987 earns good time credits automatically each month, as long as they have not been found guilty of a major misconduct or had a state law violation recorded against them. The monthly rate rises the longer the sentence has been served:2Michigan Legislature. MCL 800-33
- Years 1–2: 5 days per month
- Years 3–4: 6 days per month
- Years 5–6: 7 days per month
- Years 7–9: 9 days per month
- Years 10–14: 10 days per month
- Years 15–19: 12 days per month
- Year 20 through the end of sentence: 15 days per month
These credits are calculated in advance. When the Department of Corrections first computes a sentence, the parole eligibility date, minimum date, and maximum date are all set with the full potential regular and special good time already factored in, including any jail credit.3Michigan Department of Corrections. Policy Directive 03.01.100 – Good Time Credits
Special Good Time Credits
Eligible prisoners can also earn special good time at up to half the regular credit rate in any month. Special credits are not automatic. A committee reviews the prisoner’s institutional record and recommends the award, and the warden must concur. A prisoner can only receive special credits in a month where they also earned regular credits.3Michigan Department of Corrections. Policy Directive 03.01.100 – Good Time Credits
Combined, the two credits are substantial. A prisoner in the first two years earning both could reduce time by up to 7.5 days a month. Someone in their twentieth year could earn up to 22.5 days per month.
Proposal B and Drug Offense Exclusions
Not every pre-1987 sentence qualifies for the full benefit. Under Michigan’s 1978 Proposal B, a covered offense committed on or after December 10, 1978 but before January 1, 1983 earns good time credit only against the maximum sentence, not the minimum. Proposal B offenses committed on or after January 1, 1983 earn no good time credit at all, though disciplinary credits may still apply.3Michigan Department of Corrections. Policy Directive 03.01.100 – Good Time Credits
Prisoners serving non-life sentences for certain controlled substance violations committed on or after September 1, 1978 are excluded from good time credits altogether. They may instead earn drug law credits and disciplinary credits under a separate policy.
Disciplinary Credits for 1987 Through 2000 Offenses
For crimes committed on or after April 1, 1987, Michigan replaced good time with disciplinary credits. Eligible prisoners earn 5 days per month, provided they are not found guilty of a major misconduct. The rate does not escalate with time served.2Michigan Legislature. MCL 800-33
An additional 2 days per month in special disciplinary credits is available for good institutional conduct. A disciplinary credit committee recommends the award, the warden must concur, and the decision is based on an annual review. Special disciplinary credits cannot be awarded for any month in which the prisoner was found guilty of a major misconduct.2Michigan Legislature. MCL 800-33
The difference between the two systems is large. Under old good time, a prisoner in their tenth year could earn up to 15 days per month. Under disciplinary credits, the ceiling is 7 days per month regardless of how long the sentence runs. A Michigan appeals court described the change as replacing good time with a “less generous scheme.”4Michigan Courts. Sheriffs Good-Time Disciplinary Credits
Forfeiture Is Permanent
Under the older good time system, credits taken away for rule violations could sometimes be restored. Disciplinary credits work differently. Credits not earned in a month because of a Class I misconduct are gone permanently and cannot be restored later.3Michigan Department of Corrections. Policy Directive 03.01.100 – Good Time Credits For a long sentence, a handful of misconducts can push the parole eligibility date out by weeks or months.
Truth in Sentencing Eliminated Credits for Most Current Prisoners
Michigan’s Truth in Sentencing law, enacted in 1998, cut off good time, disciplinary credits, and corrections center placement for covered offenses. A prisoner sentenced under the law must serve the entire court-imposed minimum before the parole board can consider release.1State of Michigan: Department of Corrections. Truth in Sentencing Information
The rollout came in two phases. Assaultive crimes committed on or after December 15, 1998 were covered first. All other crimes committed on or after December 15, 2000 followed. No amount of good conduct shortens the minimum sentence for anyone in this group.1State of Michigan: Department of Corrections. Truth in Sentencing Information
This is where most of Michigan’s current prison population sits. If the offense was committed after December 2000, credits are not part of the picture, and the good time and disciplinary credit rules above will not shorten the sentence.
How Credits Affect Parole Eligibility
For prisoners who are eligible, accumulated credits are deducted from both the minimum and maximum sentence. The reduction to the minimum is what triggers parole consideration.2Michigan Legislature. MCL 800-33
The parole eligibility report must be prepared at least 90 days before the credit-adjusted minimum expires, and the parole interview must happen at least one month before that date. The rest of the parole timeline works backward from the credit-reduced minimum.5Michigan Legislature. MCL 791-235
Credits also reduce the maximum, which controls the discharge date if parole never happens. Once a prisoner is conditionally released on parole, any remaining good time or extra good time earned during that imprisonment has no further effect on the length of supervision or on future imprisonment for a parole violation.
Losing Credits and Due Process
Once a prisoner has earned good time or disciplinary credits, taking them away is treated as a substantial sanction under Michigan law. There is no constitutional right to earn credit in the first place, but stripping credit already earned implicates a liberty interest and requires due process, as the Michigan Court of Appeals held in People v. Cannon.4Michigan Courts. Sheriffs Good-Time Disciplinary Credits
In practice, credits cannot be stripped on an unsubstantiated allegation. A disciplinary hearing has to occur, the prisoner must have an opportunity to respond, and any finding of major misconduct must be documented. The record of major misconduct findings is kept and provided to the parole board with the parole eligibility report, so the effect is not limited to the lost days.2Michigan Legislature. MCL 800-33
County Jail Good Time Is a Different Rule
MCL 800.33 does not govern county jail sentences. A separate statute, MCL 51.282, gives county jail prisoners one day off for every six days of the sentence, provided they have no rule violations. That works out to roughly a 14% reduction for a prisoner who stays out of trouble.6Michigan Legislature. MCL 51-282
The sheriff has broad discretion over forfeiture and restoration. Under a general rule the sheriff can amend, the amount of good time forfeited for a rule infraction is fixed in advance. For insubordination, the sheriff can take away by special order all good time earned up to the date of the offense. As a reward for especially good conduct, the sheriff can restore some or all of the good time previously lost for minor infractions.6Michigan Legislature. MCL 51-282
The county rule matters because many misdemeanor and short-term sentences are served in a local jail rather than a state facility, and the arithmetic there is not the same as the state prison system.