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, leaving it to the discretion of the employer. Consequently, the provision of benefits is generally a matter of company policy or a result of collective bargaining agreements, rather than a legal requirement. However, under the Affordable Care Act (ACA), employers with 50 or more full-time employees (or equivalents) are required to offer health insurance to those working 30 hours or more per week or face penalties. This federal requirement indirectly influences how some employers define full-time employment for health insurance purposes. It's important for employees to review their employer's policies or their employment contract to understand the specific criteria for benefit eligibility in their workplace.