Demystifying “Truth In Sentencing” And Prison Credits In Illinois

In Illinois, people in prison can earn time off their sentences through good behavior and participation in approved prison programs. These are known as “good time credits.” How much credit a person can earn depends entirely on the conviction. The more serious the crime, the fewer good time credits a person can earn.

That gap between what a defendant could serve and what they must serve comes down to the specific charges and what the court determines at sentencing. At Pissetzky Law LLC, our attorneys step in before that moment. They will contest how charges are classified and push back against findings that would add years to the time our client must serve.

Understanding The 50% Baseline

Most standard, nonviolent felony convictions fall into the 50% tier. For every day a defendant serves without a serious disciplinary infraction, they earn one day off their remaining sentence. If a judge announces a 10-year sentence, a person may be able to serve just half of that through good behavior.

Sex Crimes Have An 85% Baseline

For people convicted of sexual assault and aggravated sexual assault, the law requires them to serve at least 85% of their sentence. In other words, their good time credits can only lessen their sentence by 15%. A 10-year sentence means at least 8.5 years inside, regardless of in-prison behavior.

Repeat convictions for predatory sexual assault of a child can carry a natural life sentence with zero sentence credit. Illinois law provides no release mechanism in these cases.

Beyond the prison term, sex offense convictions in Illinois require a period of Mandatory Supervised Release (MSR). MSR functions like parole. A person convicted of these crimes must comply with strict court-imposed conditions and report regularly to a supervising officer. Any violation can trigger reincarceration.

Violent Crimes Can Have Varying Good Time Credit Baselines

For those convicted of violent crimes, the amount of good time credit they can earn depends on the severity of the offense.

First-degree murder sits on the 100% tier

People convicted of first-degree murder must serve their full sentence. No behavioral credits or in-prison programming can reduce this time, and this requirement carries no exceptions.

Some violent offenses sit on the 85% tier

This includes attempted first-degree murder and aggravated discharge of a firearm. If convicted, a person may be able to lessen up to 15% of their full sentence through good behavior. If they have a 20-year sentence, they must serve at least 17 years before any possibility of release.

“Great bodily harm” can affect prison sentence credits

Several charges, including home invasion and armed robbery, ordinarily fall into the 50% default tier. However, if the court finds that the victim suffered serious physical injury or “great bodily harm” as a result of the defendant’s actions, Illinois law moves those same offenses into the 85% tier. The charge itself does not change. The required time served does.

Class X Drug Convictions Have A 75% Baseline

Class X is the most serious felony classification in Illinois below murder. Illinois law places certain Class X drug convictions into a 75% tier when the offense involves 100 grams or more of a controlled substance such as cocaine, heroin or fentanyl.

One narrow exception applies. Defendants in the 75% tier can reduce their required time to 60% by completing specific, approved in-prison programs. This often includes substance abuse treatment and educational or vocational training. However, the right programs have to be available at the facility, and the defendant has to qualify for them. Building toward this reduction starts at sentencing.

How We Fight These Tiers Before Sentencing

The presentencing stage is where outcomes can still change, and that is where attorney Gal Pissetzky focuses the defense. He builds his strategies toward the lowest tier possible by:

• Negotiating the charge down to a lower felony classification before sentencing, which can move a defendant out of a higher tier entirely
• Contesting a great bodily harm finding before the judge formally enters it, keeping an offense in the 50% tier rather than the 85% tier
• Presenting a structured sentencing argument based on the specific facts of the case to reach the lowest tier the law allows

Get in touch with us today to schedule a consultation with attorney Pissetzky. He can walk you through the strategies that apply to you or your loved one’s situation.

Common Questions About Illinois Truth In Sentencing

Below are some of the questions we often receive from our clients. If your specific situation is not covered here, call us at 312-239-8292 to speak directly with a member of our legal team.

Can jail credit or in-prison programming drop a 75% or 85% sentence lower?

If you are locked into a mandatory 85% tier for a violent crime or a 100% day-for-day hold for murder, the law strictly prohibits the IDOC from reducing your actual time inside below those statutory minimums through behavioral or programming credits.

However, there is a narrow window for drug offenses: individuals serving a mandatory 75% Class X drug sentence can actively reduce their time down to a 60% tier by successfully completing rigorous, approved in-prison substance abuse rehabilitation, educational degrees or technical vocational training. Because these credits depend heavily on prison resources and strict institutional eligibility, securing these reductions requires meticulous tracking and aggressive defense advocates who understand how to structure these directives from day one.

What is the difference between “Good Behavior Credit” and “Earned Discretionary Sentence Credit”?

“Good Behavior Credit” (statutory sentence credit) is the baseline day-for-day credit that automatically reduces standard nonviolent felony sentences to 50%, provided the individual avoids severe disciplinary infractions while incarcerated.

Conversely, Earned Discretionary Sentence Credit (EDSC) is supplemental time off granted entirely at the sole discretion of the IDOC Director for exceptional acts, compliance, or targeted programming. Eligible individuals serving sentences under five years can be awarded up to 180 days of EDSC, while those serving sentences of five years or longer can potentially earn up to 365 days off. However, individuals serving 85% or 100% mandatory terms are legally barred from using EDSC to bypass their statutory minimums.

Do you receive sentencing credit for time spent on pretrial electronic monitoring (EM)?

Under Illinois law, individuals placed on pretrial electronic monitoring or home detention are entitled to receive credit for time served against their ultimate prison sentence. However, prosecutors routinely challenge this credit by arguing technicalities regarding the “custodial” nature of the tracking system or the specific curfew guidelines established by the court.

Because the laws governing pretrial detention credits are continuously litigated and subjected to legislative shifts, ensuring your time on a monitor actually counts toward your freedom requires a trial defense team that aggressively mandates the proper calculation of day-for-day pretrial credits during final sentencing hearings.

Talk To A Trial-Ready Defense Attorney Today

If you or a loved one faces state charges with heavy sentencing minimums under Truth in Sentencing, do not wait for a conviction to understand the stakes. Call us at 312-239-8292 or schedule a case review with our team today.