WARN Act 101: When 60-Day Layoff Notice Is Required
The federal WARN Act can require 60 days' advance notice before mass layoffs or plant closings. Here's who's covered and what counts as a triggering event.
By Nora Ellison · Senior HR Compliance Writer
Reviewed by theComplianceToolsLibrary Editorial Team · · 5 min read
The Worker Adjustment and Retraining Notification (WARN) Act requires certain employers to give 60 calendar days' advance written notice before a plant closing or mass layoff. The goal is to give workers and communities time to adjust.
WARN is full of thresholds and counting rules, and several states have their own "mini-WARN" laws that are stricter. Start with the federal framework, then check your state.
Which employers are covered
Federal WARN applies to employers with 100 or more full-time employees, or 100 or more employees who together work at least 4,000 hours per week (excluding overtime).
What triggers notice
Two main events trigger WARN, each measured at a single site of employment over a 90-day window:
- Plant closing: a shutdown of a site (or unit) causing employment loss for 50 or more full-time employees.
- Mass layoff: employment loss for 500+ full-time employees, or for 50–499 employees if they make up at least 33% of the active full-time workforce at the site.
What 'employment loss' means
Employment loss includes a termination (other than for cause, resignation, or retirement), a layoff exceeding six months, or a reduction of more than 50% in hours in each month of a six-month period. Brief layoffs that don't cross those lines may not count.
Who must receive notice — and exceptions
Notice goes to affected workers (or their union), the state dislocated-worker unit, and the chief elected local official. Limited exceptions — such as a faltering company, unforeseeable business circumstances, or a natural disaster — can shorten but rarely eliminate the notice obligation.
Sources
Frequently asked questions
How much notice does the WARN Act require?
60 calendar days of advance written notice before a covered plant closing or mass layoff.
Which employers have to comply with WARN?
Employers with 100 or more full-time employees, or 100 or more employees who work a combined 4,000+ hours per week excluding overtime.
Are there exceptions to the 60-day notice?
Yes — faltering company, unforeseeable business circumstances, and natural disaster exceptions can reduce the notice period, but the employer must still give as much notice as practicable and explain the shortfall.