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Legal Compliance Guide

Illinois Overtime Laws 2026: 40-Hour Weekly Rule & Regular Rate Formulas

Published by the StateWageCalc Editorial Team • Current as of October 2026

1. Statutory Standard: 820 ILCS 105/4a

In Illinois, overtime compensation is governed by Section 4a of the Illinois Minimum Wage Law (820 ILCS 105/4a) and the federal Fair Labor Standards Act (FLSA, 29 U.S.C. § 207). Nonexempt employees must receive overtime compensation at a rate of not less than 1.5 times their regular rate of pay for all hours worked in excess of 40 during a single 7-day workweek.

Unlike states such as California, Illinois does not mandate daily overtime premiums for working more than 8 hours in a single workday. Overtime is triggered strictly when cumulative hours in the designated workweek exceed 40.

2. Determining the Regular Rate of Pay (RROP)

Under 820 ILCS 105/4a and federal regulations (29 C.F.R. Part 778), an employee's regular rate is not simply their nominal base wage. It encompasses all remuneration paid to the employee for work performed, with limited statutory exclusions (such as gifts, discretionary bonuses, and expense reimbursements).

Core Regular Rate Formulas

Hourly Workers with Bonuses:
Regular Rate = (Total Hourly Straight Time + Nondiscretionary Bonuses + Commissions) ÷ Total Hours Worked

Fixed 40-Hour Salary Arrangement:
Base Regular Rate = Fixed Salary ÷ 40
Base Overtime = Overtime Hours × 1.5 × Base Regular Rate
Bonus Hourly Contribution = Bonus ÷ Total Hours
Bonus Overtime Premium = Overtime Hours × 0.5 × Bonus Hourly Contribution

3. Statutory Minimum Overtime Floors by Jurisdiction

Because an employee's regular rate can never lawfully fall below the governing statutory minimum wage, the overtime rate cannot fall below 1.5 times that minimum wage:

  • Illinois Statewide: $15.00 × 1.5 = $22.50 per hour
  • City of Chicago (July 1, 2026): $17.05 × 1.5 = $25.575 per hour
  • Cook County Covered (July 1, 2026): $15.40 × 1.5 = $23.10 per hour

4. Fluctuating Workweek Method (FWW) in Illinois

Under 29 C.F.R. § 778.114, an employer and nonexempt employee may agree to a fluctuating workweek pay plan where a fixed salary pays straight time for all hours worked in a week, and overtime is compensated at only half-time (0.5×). However, this method requires strict compliance:

  • A clear mutual understanding between employer and employee must exist before work begins.
  • The employee's hours must genuinely fluctuate above and below 40 from week to week.
  • The salary must be paid in full regardless of whether the employee works fewer than 40 hours.
  • The resulting regular rate (salary ÷ total hours) must never fall below the applicable statutory minimum wage in any week.

5. 300% Punitive Damages Under 820 ILCS 105/12

Illinois imposes some of the strictest penalties in the United States for unpaid overtime. Under 820 ILCS 105/12:

Remedies for Underpaid Overtime:

  • 100% of all unpaid overtime compensation owed.
  • 300% statutory punitive damages (triple damages).
  • 5% monthly penalty on unpaid amounts payable directly to the employee.
  • Mandatory award of reasonable attorney fees and court costs.