In Illinois a cosmetology program must be at least 1,500 clock hours. By law the program must extend over no less than 8 months (and no more than 7 consecutive years), so the fastest you can finish an approved cosmetology course is about 8 months (full‑time). Part‑time schedules will take longer — many schools offer 9–18 month programs depending on hours per week. (ilga.gov)

If you meant a different program: esthetics is 750 hours (shorter), and teacher/clinic teacher programs have different hour requirements. (law.cornell.edu)