Understanding the concept of “hours worked” is crucial to complying with the FLSA. According to the U.S. Supreme Court [Tn. Coal, Iron & R.R. Co. v. Muscodol Local No.123, 321 U.S. 590 (1944)], an employee must be compensated for “all time spent in physical or mental exertion (whether burdensome or not) controlled or required by the employer and pursued necessarily and primarily for the benefit of the employer.”

The courts and the U.S. Department of Labor, however, have recognized that insubstantial or insignificant periods of time outside scheduled working hours may be disregarded in recording working time. 29 C.F.R. § 785.47. The rule applies only where a few minutes of work are involved and where the failure to count such time is due to considerations justified by “operational realities.” Such time is called “de minimis” (i.e., minor or trivial). The Portal-to-Portal Act of 1947 helps clarify the working-time issue. (See the discussion of the Portal-to-Portal Act in this section under Travel Time.)

Employees who, with the knowledge or consent of their employer, continue to work after their shifts are over, though voluntarily, are engaged in compensable working time. The reason for the work is immaterial; as long as the employer “suffers or permits” employees to work on its behalf, overtime compensation may be due. 20 C.F.R. § 785.11. This is true whether the work takes place at the place of business or at the employee’s home. For example, activities such as filling out reports, attending “roll call,” and returning to the station after completing a call are all compensable work if done at the employer’s behest and for the employer’s benefit.