ERISA 1,000-hour rule

The 1,000-hour rule is an eligibility standard under ERISA, the federal law governing private-sector retirement plans. An employer that sponsors a qualified retirement plan generally cannot exclude an employee from participating solely for being "part-time" if that employee completes at least 1,000 hours of service during a 12-month period.

In practice, 1,000 hours works out to roughly 20 hours per week over a full year. So a retail associate who works half-time all year, or a seasonal worker who logs heavy hours for several months, can cross the threshold and earn the right to join the company's 401(k) or pension plan — the same as a full-time colleague. Hours of service include paid time such as vacation and sick leave, not just hours actually worked.

The rule matters because it prevents employers from labeling workers part-time to keep them out of retirement benefits. It works alongside ERISA's other participation standards, such as minimum age and service requirements, and its vesting rules that determine when employer contributions belong to the employee. More recent federal legislation has further expanded eligibility for long-term part-time employees with fewer annual hours, reinforcing the same policy goal.

Life and health insurance licensing exams test the 1,000-hour rule as part of ERISA's corporate retirement plan standards. Be ready to identify 1,000 hours in a 12-month period as the service threshold that entitles a part-time employee to plan participation.