Illinois Sentencing Guidelines: Felony and Misdemeanor Ranges

Illinois sentencing guidelines work by classification: every criminal offense is placed into a statutory class, and each class carries a defined range of prison or jail time, a maximum fine, and a period of supervision after release. The Unified Code of Corrections sets those ranges, and the judge picks a number inside the range based on the facts of the case and the defendant’s history. Sentence credits, mandatory enhancements, and post-prison supervision then shape what a person actually serves.

Felony Classes and Their Ranges

Illinois has six felony tiers. Every felony can also carry a fine of up to $25,000 per offense.1Illinois General Assembly. Illinois Code 730 ILCS 5/5-4.5-50 – Sentence Provisions, All Felonies

Second degree murder is a Class 1 felony but sits in a wider 4-to-20-year range rather than the standard Class 1 cap of 15 years, and probation is possible in some cases, which is unusual for a homicide conviction.

Misdemeanor Classes and Their Ranges

Misdemeanors are served in county jail, not state prison, and Illinois splits them into three classes.

Judges have far more flexibility at the misdemeanor level. Community service, court supervision, and conditional discharge are all available, and because the ceiling stays under a year, the collateral consequences that follow a felony record are avoided.

When Probation Is Available

Not every felony conviction leads to prison. For Class 1 through Class 4 felonies, a judge can impose probation instead of incarceration. The maximum probation term is 4 years for Class 1 and Class 2 felonies, and 30 months for Class 3 and Class 4 felonies.5Illinois General Assembly. Illinois Code 730 ILCS 5/5-4.5-30 – Class 1 Felonies, Sentence6Illinois General Assembly. Illinois Code 730 ILCS 5/5-4.5-35 – Class 2 Felonies, Sentence7Illinois General Assembly. Illinois Code 730 ILCS 5/5-4.5-40 – Class 3 Felonies, Sentence8Illinois General Assembly. Illinois Code 730 ILCS 5/5-4.5-45 – Class 4 Felonies, Sentence

Class X felonies and first degree murder are never eligible.4Illinois General Assembly. Illinois Code 730 ILCS 5/5-4.5-25 – Class X Felonies, Sentence Class 1 probation is also unavailable if the offense was committed while the defendant was already on probation for another felony.5Illinois General Assembly. Illinois Code 730 ILCS 5/5-4.5-30 – Class 1 Felonies, Sentence Certain violent and drug offenses carry their own probation bars regardless of class, so the charge itself matters as much as the tier.

How Judges Choose a Number in the Range

Inside every range, the judge decides where the sentence lands by weighing mitigating and aggravating factors. The gap between the floor and ceiling of a range can be years or decades, and this is where most of the real work of sentencing happens.

Mitigating Factors

Mitigating factors push the sentence toward the low end. The statute lists grounds a court should consider, including no significant criminal history, an offense that did not cause or threaten serious physical harm, and strong provocation.11Illinois General Assembly. Illinois Code 730 ILCS 5/5-5-3.1 – Factors in Mitigation Evidence that the defendant is likely to comply with probation conditions, or that imprisonment would cause excessive hardship on dependents, also weighs in the defendant’s favor. Where probation is on the table, these factors often make the difference between prison and probation.

Aggravating Factors

Aggravating factors justify a sentence closer to the maximum. Courts look at whether the defendant was paid to commit the offense, whether the crime involved exceptional brutality, and whether the victim was particularly vulnerable because of age or disability.12Illinois General Assembly. Illinois Code 730 ILCS 5/5-5-3.2 – Factors in Aggravation and Extended-Term Sentencing Prior criminal history is one of the most powerful. Courts also consider whether the defendant held a position of trust that facilitated the crime, or whether the offense was gang-related. Judges must state their reasoning on the record, and the weight given to these factors is reviewable on appeal.

Extended-Term Sentences

Under specific circumstances, a judge can impose an extended-term sentence that roughly doubles the standard maximum for the class:

Eligibility is triggered by specific statutory factors. The most common is a prior conviction of the same class or a more serious class within the previous ten years, not counting time in custody.12Illinois General Assembly. Illinois Code 730 ILCS 5/5-5-3.2 – Factors in Aggravation and Extended-Term Sentencing Other paths include offenses involving exceptionally brutal behavior, victims under 12 or over 60, organized gang activity, or use of a firearm with a laser sight. The judge must find a statutory factor and document the basis on the record.13Illinois General Assembly. Illinois Code 730 ILCS 5/5-8-2 – Extended Term

Firearm Enhancements

Illinois imposes some of the steepest firearm enhancements in the country. For a list of serious offenses that includes first degree murder, armed robbery, aggravated criminal sexual assault, aggravated kidnapping, and home invasion, the court adds mandatory prison time on top of the base sentence:3Illinois General Assembly. Illinois Code 730 ILCS 5/5-8-1 – Natural Life Imprisonment, Enhancements for Use of a Firearm, Mandatory Supervised Release Terms

  • Possessing a firearm during the offense: 15 years added
  • Personally discharging a firearm: 20 years added
  • Discharge causing great bodily harm, permanent disability, or death: 25 years to natural life added

These years are mandatory and stack. Armed robbery is a Class X felony with a 6-to-30-year range; a defendant who fired a gun and seriously injured someone during that robbery faces the underlying sentence plus an additional 25 years to life. The math climbs fast, and firearm exposure is often the first place a defendant facing violent charges sees how serious the stakes are.

Multiple Counts: Concurrent or Consecutive

When a defendant is convicted of more than one offense, the default is that sentences run at the same time. No reason is required for concurrent sentences; that is the baseline.14Illinois General Assembly. Illinois Code 730 ILCS 5/5-8-4 – Concurrent and Consecutive Terms of Imprisonment

A judge can order sentences to run back-to-back only in specific circumstances. The most common ground is a finding that consecutive terms are necessary to protect the public from further criminal conduct, which the court must explain on the record. Consecutive sentencing is also permitted when a defendant commits a new felony while on pretrial release or while detained in a county jail, or when a person in custody commits battery against a correctional officer.14Illinois General Assembly. Illinois Code 730 ILCS 5/5-8-4 – Concurrent and Consecutive Terms of Imprisonment A misdemeanor sentence a defendant is already serving merges into a new felony sentence and runs concurrently.

How Much of the Sentence Is Actually Served

The number a judge announces in court is rarely the exact time served. Illinois uses a tiered system of sentence credits that fixes what percentage of the term must be completed before release.

100% Offenses

Defendants convicted of first degree murder or terrorism earn no sentence credit and must serve the entire term.15Illinois General Assembly. Illinois Code 730 ILCS 5/3-6-3 – Rules and Regulations for Sentence Credit

85% Offenses

A second tier of serious violent crimes requires the defendant to serve at least 85% of the sentence. This category includes attempted murder, predatory criminal sexual assault of a child, aggravated criminal sexual assault, aggravated kidnapping, and aggravated battery with a firearm, among others. Inmates in this tier can earn no more than 4.5 days of credit per month.15Illinois General Assembly. Illinois Code 730 ILCS 5/3-6-3 – Rules and Regulations for Sentence Credit

Day-for-Day (50%) Offenses

Most other felonies fall under day-for-day credit: one day off for each day served. A 10-year sentence for a qualifying offense can result in release after roughly 5 years if the person follows facility rules and stays clear of disciplinary violations.16Illinois General Assembly. Illinois Code 730 ILCS 5/3-6-3 – Rules and Regulations for Sentence Credit Day-for-day credit is not guaranteed; it depends on good behavior, and the Department of Corrections can revoke earned credit for disciplinary infractions.

Earned Program Credits

Beyond good conduct credit, inmates who participate in approved programs can earn additional days. Full-time participation in substance abuse treatment, education, vocational training, life skills courses, or reentry planning earns one day of credit per day of participation, and finishing high school equivalency or a college degree in custody produces lump-sum credits.17Illinois Sentencing Policy Advisory Council. Sentence Credits 101 Other assignments, volunteer work, and self-improvement programs that do not qualify for full credit can still earn up to half a day per day of participation. Inmates serving 100% sentences for murder or terrorism are excluded from this system entirely.

Mandatory Supervised Release After Prison

This is the part of Illinois sentencing that catches many people off guard. Once the prison portion ends, every felony conviction carries a period of mandatory supervised release (MSR) that functions like parole. During MSR, the person must follow conditions set by the Prisoner Review Board, and a violation can send them back to prison.

MSR terms are set by statute:

MSR is not optional and is not part of the prison sentence. It is a separate, additional period of state supervision that starts on the day of release. Failing to report, picking up a new criminal charge, or violating any release condition can result in reincarceration for the remaining MSR time.

Credit for Time Already Served

A defendant who spent time in county jail before sentencing receives credit toward the final prison term for every day held in custody on the case. This is automatic and does not depend on the judge’s discretion.18FindLaw. Illinois Code 730 ILCS 5/5-4.5-100 – Calculation of Term of Imprisonment Four months in jail awaiting trial on a three-year sentence means those four months count toward the three years.

Credit can also apply to time spent in home detention with electronic monitoring or curfew restrictions of 12 or more hours per day, at the court’s discretion, and to time in court-ordered psychiatric or substance abuse treatment before sentencing. One exception matters: if the new offense was committed while the defendant was on parole, probation, or MSR, time spent in custody for a revocation of that earlier status does not automatically count toward the new sentence unless both the prosecution and the defense agree to credit it.18FindLaw. Illinois Code 730 ILCS 5/5-4.5-100 – Calculation of Term of Imprisonment