WARN Act and Part-Time Workers: Counted Out of the Thresholds, Not Out of Notice

If you work part-time and your workplace announces a mass layoff, it is natural to wonder whether the WARN Act covers you at all. The short answer is more generous than most people expect, but it comes with a catch. Part-time workers are left out of the headcounts that decide whether the law applies. Once the law does apply, though, they are not left out of the notice.

That distinction is the whole story.

Who counts as part-time under WARN

The federal WARN Act defines a part-time employee in two ways: an average of fewer than 20 hours per week, or fewer than six months worked in the 12 months before notice would be required. A worker averaging 15 hours a week for three years is part-time under the first test. A worker averaging 40 hours a week but hired only two months ago is part-time under the second.

Everyone else counts as full-time for WARN purposes. Job titles do not decide this; hours and tenure do.

Where part-timers are left out of the count

Part-time workers are excluded from three headcounts that switch the law on.

First, the employer test. A private employer is covered if it has 100 or more full-time employees. Part-time workers do not count toward that 100. There is a second route: 100 or more employees, full-time and part-time combined, who together work at least 4,000 hours per week, excluding overtime. Part-timers do count toward the hours in that alternative test.

Second, the plant-closing trigger. A shutdown counts as a plant closing when it causes employment loss for 50 or more employees, excluding part-time employees, at a single site during a 30-day period.

Third, the mass-layoff trigger. A layoff counts when it causes employment loss for at least 500 employees, excluding part-time employees, or for at least 50 employees, excluding part-time employees, who make up at least one-third of the full-time workforce at that site.

In all three counts, the law measures the core full-time workforce. That is why a layoff that feels large can still fall outside federal law: if too many affected workers are part-time, the counted numbers may never reach the trigger.

The part most people miss: notice is still owed

Here is the twist. Once a plant closing or mass layoff is covered — once the counted full-time numbers reach the trigger — the notice itself goes to every affected employee, part-time included. The Department of Labor's employer guidance makes this point explicitly: part-time employees do not count toward the 100-employee threshold, but they are entitled to notice if they are affected by a covered event.

So the exclusion is about switching the law on, not about who receives the warning once it is on. A part-time cashier at a covered store closing gets the same 60 days of written notice as the full-time cashier beside them.

Two worked examples

Consider a company with 90 full-time employees and 30 part-time employees averaging 15 hours a week. On the 100 full-time test it is not covered. But under the hours test, the combined workforce works 90 times 40 plus 30 times 15 hours, which is 4,050 hours a week — above the 4,000-hour line. The company is covered after all.

Now consider a site with 200 full-time employees where the employer lays off 60 full-time and 60 part-time workers. Only the 60 full-time workers count. Sixty is at least 50, but 60 out of 200 is 30 percent, below the one-third requirement and far below 500. So this is not a covered mass layoff, even though 120 people lose their jobs. If the site had only 150 full-time employees, 60 would be 40 percent, the layoff would be covered, and all 120 affected workers would be owed notice.

These are illustrations, not reports of real filings. Small changes in the full-time headcount flip the outcome; the part-time headcount never does.

State laws can be stricter

Federal law is a floor, not a ceiling. California's Cal-WARN law, for example, uses a 75-employee threshold that includes part-time workers, and its mass-layoff trigger has no one-third rule. A layoff that escapes federal WARN because of its part-time mix may still be covered by state law.

If you are part-time and got no notice

Check whether the event was covered at all, and check your state's mini-WARN law, which may cover smaller employers or count part-timers. Keep records with dates: when you were told, when your last day is, and how many hours you averaged. Contact your state's Rapid Response team, and file for unemployment promptly; eligibility does not depend on whether WARN notice was given.

The numbers behind this article

These are reported plans, not confirmed job losses. Coverage and reporting rules vary by state, so the registry is not a census of layoffs.

Layoff Atlas currently shows 670 notices covering 63,560 reported workers in its 90-day window, with 33 notices carrying no worker count, updated October 26, 2026. Washington (16,960) and California (13,557) lead, followed by Illinois (4,626), Texas (3,652), and Georgia (2,492). The registry's upcoming weekly buckets list 7,743 workers for the week of October 27, 2,827 for November 3, 6,838 for November 10, 6,556 for November 17, 9,123 for November 24, and 2,218 for December 1.

Data source: Layoff Atlas