The number of hours an employee must work to be considered full-time and eligible for employee benefits such as health insurance, paid time off (including vacation leave and sick leave), and retirement accounts (401k and related employer-contributions) is generally in the sole discretion of the employer. This is because an employer is not obligated to provide these employee benefits or fringe benefits to any employee, whether full-time or part-time.

For example, the Fair Labor Standards Act (FLSA) does not define full-time employment or part-time employment. And whether an employee is considered full-time or part-time does not change the application of the FLSA—or the application of the Service Contract Act (41 US.C. §351) or the Davis-Bacon Act wage and fringe benefit requirements (40 U.S.C. §3141).

In Massachusetts, the definition of full-time employment and the number of hours an employee must work to be considered full-time for the purpose of eligibility for employee benefits such as health insurance, paid time off, and retirement accounts is typically determined by the employer. There is no specific state statute that defines full-time employment for these benefits. The Fair Labor Standards Act (FLSA), which is federal law, also does not define full-time or part-time employment, meaning that the provision of benefits is largely at the discretion of the employer. However, under the Affordable Care Act (ACA), employers with 50 or more full-time employees (including full-time equivalent employees) are required to offer health insurance to those working at least 30 hours per week on average or face penalties. This federal requirement may influence how employers define full-time employment for the purposes of health insurance benefits. For other benefits, such as paid time off and retirement accounts, employers in Massachusetts are free to establish their own criteria for eligibility.