Federal law does not set any upper bound on the number of hours an employer can require most employees to work. However, both the federal Fair Labor Standards Act and state laws restrict the length of the work day and work week for some minors. In addition, many workers who put in more than 40 hours in a single work week are entitled to overtime pay.

FLSA Overtime Rules

Employees who are at least 16 years old can work any number of hours. There’s no federal provision for extra pay for working on a weekend, holiday or for workdays exceeding eight hours. However, when an employee puts in more than 40 hours in a week, she must be paid at an overtime rate not less than 1 1/2 times her regular hourly rate. The FLSA allows employers to start and end a work week on any day and at any time of day, However, a work week must consist of seven consecutive 24-hour days. Some states add additional requirements governing hours worked and overtime pay.

Work Hours for Youth

The FLSA permits children ages 14 and 15 to work, but limits the hours and times they may do so. Youths may not work during school hours and can work no more than three hours a day and 18 hours a week when attending school. During the summer, they can work up to eight hours a day and 40 hours per week. Work hours must be between 7 a.m. and 7 p.m., or 9 p.m. during summer months. States may add restrictions on youth labor. Some states require workers under age 16 to obtain work permits. Some add further limits on times of day children may work or restrict the number of days worked each week.

What Time Counts

According to the U.S. Department of Labor, a worker is legally working when an employer requires her to be on duty or present at a job location, even if she is only waiting for something to do. A posted work schedule doesn’t determine the hours a worker is paid. Rather, the work period begins when the employee starts working and ends when she stops. Employers must pay workers for extra time worked, even if it is voluntary. For example, if a clerk stays past her scheduled quitting time to finish helping a client, she must be compensated for her time. Short breaks of 20 minutes duration or less generally are paid time. Meal breaks of 30 minutes or longer may be unpaid, provided the worker has no duties during the break period.

Calculating Overtime

Suppose a worker normally earns $12 an hour and works 44 hours one week. To figure his pay, multiply $12 times 44 hours and you get $528. Multiply the four hours overtime by $6 for an additional $24. Add the amounts and the total pay comes to $552. Hours and pay cannot be averaged for biweekly pay periods. For instance, an employee who works 30 hours one week and 50 the next receives 10 hours overtime for the second week, even though she averaged 40 hours per week for the pay period.

State Hours Worked Laws

Individual states have a variety of labor laws that affect how many hours someone can work before he is entitled to overtime. For example, Alaska and Nevada require employers to pay time and a half for hours worked in excess of eight hours in a single day. California and Kentucky mandate time and a half for the seventh day an employee works in a week even if total hours do not add up to 40. Rhode Island labor law says employers must pay overtime for hours worked on holidays or Sundays. Check with your state’s department of labor for specific requirements that may apply.