Illinois Criminal Sentencing Guidelines Calculator

Illinois uses a **determinate sentencing** system — the judge imposes a fixed term within a statutory range for each offense class (730 ILCS 5/5-4.5). There is no parole for offenses committed after **February 1, 1978** (the "truth-in-sentencing" era began here). The type of system — determinate vs. indeterminate — determines whether the judge or a parole board controls actual release.

First-degree murder: **20–60 years** (730 ILCS 5/5-4.5-20). Class X felonies (armed robbery, home invasion): **6–30 years**, no probation. Firearm enhancements add **15–25 years** for discharge during a felony (§ 5-8-1(a)(1)(d)(iii)). Mandatory minimums remove judicial discretion for specific offenses — the judge cannot sentence below the statutory floor regardless of circumstances.

Probation for Class 3/4 felonies runs **up to 30 months**; Class 1/2 felonies **up to 4 years** (730 ILCS 5/5-4.5). Class X felonies are **ineligible** for probation. First Offender Probation (§ 5-6-3.4) is available for certain drug possession charges — successful completion results in dismissal. Probation keeps a defendant out of prison under court-imposed conditions — but not every offense qualifies.

Day-for-day credit (**50%** reduction) applies to most offenses. Truth-in-sentencing offenses (first-degree murder, sexual assault, armed robbery — 730 ILCS 5/3-6-3(a)(2)) require serving **85–100%** of the sentence. The 2022 SAFE-T Act expanded sentence credits for program participation. Good-time credits can dramatically reduce actual time served — understanding the rules is essential for estimating a realistic release date.

A Illinois criminal sentencing calculator should distinguish the sentence pronounced by the judge from expected time served. Jail credit, prison classification, earned-time rules, parole eligibility, probation eligibility, and mandatory-minimum statutes can all change the practical outcome.

• Charge level, offense class, count number, and statutory range.
• Prior record, enhancements, victim injury, weapon allegations, and drug quantity.
• Mandatory minimums, probation eligibility, diversion, and plea offer terms.
• Jail credit, good-time credit, parole eligibility, and consecutive versus concurrent time.
• Fine, court costs, restitution, supervision fees, and collateral consequences.

Treat the output as a planning range, not a promise. Judges, prosecutors, probation departments, and plea negotiations can all move the number. Use the estimate to prepare questions for a defense lawyer about the best-case, likely, and worst-case outcomes before deciding whether to plead or fight.

Illinois cost and deadline signals is the right starting point because statewide law sets the baseline, while the facts of your criminal case determine the actual risk band. Use the calculator before you compare attorney quotes, court options, or settlement choices.

Factors that affect the Illinois estimate usually comes down to three inputs: the amount at stake, the deadline or statutory rule, and whether the matter can be resolved before a contested filing. The calculator keeps those inputs separate so the result is easier to challenge.

County variation matters in Illinois because clerk practices, hearing calendars, and local filing steps can change the time cost even when the statewide rule is fixed.

• Cook County: 5,267,072 residents, county seat in Chicago.
• DuPage County: 931,508 residents, county seat in Wheaton.
• Lake County: 713,426 residents, county seat in Waukegan.
• Will County: 696,909 residents, county seat in Joliet.
• Kane County: 516,403 residents, county seat in Geneva.

1. Run the calculator with your current numbers and save the 2026 result.
2. Compare the result with documents, notices, invoices, or deadlines already in hand.
3. Use the estimate to prepare a focused consultation or filing plan before the next deadline.