---
title: "What is the difference between Class 4, Class 2, and Class X felony Illinois DUI?"
description: "Illinois aggravated DUI severity is set by the specific subsection of 625 ILCS 5/11-501(d). Class 4 felony DUI carries 1 to 3 years prison and covers offenses like third DUI or driving without a..."
url: https://chicagoduilawyer.net/faq-items/what-is-the-difference-between-class-4-class-2-and-class-x-felony-illinois-dui/
date: 2026-07-08
modified: 2026-07-08
author: "Chicago DUI Lawyer"
type: faq
lang: en
---

# What is the difference between Class 4, Class 2, and Class X felony Illinois DUI?

Illinois aggravated DUI severity is set by the specific subsection of 625 ILCS 5/11-501(d). Class 4 felony DUI carries 1 to 3 years prison and covers offenses like third DUI or driving without a license during DUI. Class 2 felony DUI carries 3 to 7 years and typically applies to fourth or fifth offense, or DUI causing great bodily harm. Class X felony DUI carries 6 to 30 years and applies to a sixth DUI or DUI causing multiple deaths. Non-probationable classes leave zero sentencing flexibility. The chicagoduilawyer.net defense priority in Class 2 and above cases is factual reclassification before it reaches sentencing math.