Part-Time Employees and Group Health Insurance
The ACA created a bright-line rule: employees working 30 or more hours per week on average are considered "full-time" for employer mandate purposes. Applicable Large Employers (ALEs — 50+ FTE) must offer coverage to these full-time employees or face potential penalties. Employees working fewer than 30 hours per week are not required to be offered coverage under the federal mandate, though California has no additional state mandate at this time.
For ALEs, determining which employees are "full-time" for a variable-hour workforce requires a measurement system. The IRS provides two methods: the monthly measurement method (determine status month by month based on that month's hours) and the look-back measurement method (track hours over a 3–12 month measurement period, then grant or deny coverage for an equal stability period).
Look-Back Measurement Method in Practice
Example: 12-month measurement period, January 1 – December 31 of Year 1. Administrative period: January 1 – February 28 of Year 2 (enrollment). Stability period: March 1, Year 2 – February 28, Year 3. An employee who averaged 32 hours/week in Year 1 must be offered coverage starting March 1, Year 2, and that coverage must continue through February 28, Year 3 — even if the employee drops to part-time hours during the stability period. This protects employees from coverage instability.
Voluntary Coverage for Part-Time Employees
Employers are not prohibited from offering coverage to part-time employees — they simply aren't required to. Voluntarily extending coverage to part-time employees (those working 20+ hours/week, for example) can be a powerful retention and recruitment tool in industries like retail, hospitality, and food service where part-time employees are common and competitors rarely offer coverage. The cost is real but the differentiation is significant.
FTE Calculation Includes Part-Time Hours
Even if you don't offer part-time employees coverage, their hours count toward the FTE calculation that determines if you're an ALE. A restaurant with 20 full-time cooks and 50 part-time servers working 20 hours/week: 20 + (50 × 20/120) = 28.33 FTE — likely not an ALE. But 30 full-time and 60 part-time servers: 30 + (60 × 20/120) = 40 FTE — still not, but getting close. Add a sister location and you might cross 50. Track this carefully as your business grows.