While states may adopt their own laws regarding wages and overtime, Illinois law mostly follows the federal Fair Labor Standards Act (FLSA). Overtime laws apply to salaried employees as well as those who are paid by the hour. Under Illinois and federal law, some white collar workers are exempt from overtime wages---meaning, employers are not mandated to pay those workers for overtime.
Minimum Wage and Overtime Rate
If an Illinois employee works more than 40 hours in a workweek, the employer must pay at least 1.5 times the employee's hourly rate for each overtime hour worked. The hourly rate must be at least minimum wage, which is $8.25 in Illinois for persons 18 years of age or beyond. The federal minimum wage is $7.25 but, according to the U.S. Department of Labor, in cases "where federal and state law have different minimum wage rates, the higher standard applies."
The FLSA defines the workweek as 168 consecutive hours, or seven consecutive 24-hour periods. The workweek doesn't have to correspond with calendar weeks; the employer can choose any hour of any day for the start of the workweek. However, federal and Illinois law forbids employers from lumping two workweeks together and basing overtime pay on 80 hours instead of 40.
Illinois follows federal guidelines for identifying certain occupations as exempt from overtime pay rights. Salaried administrators, professionals, computer experts who earn at least $455 per week are exempt under federal and Illinois law, as are salespeople who work on commission and employees earning an annual salary of $100,000 or more. Illinois adds a few more exemptions not included in the federal law; salesmen and mechanics at automotive dealerships, agricultural laborers, some employees of radio and TV stations in small cities and some employees of educational and residential child care facilities.