The WARN Act, or Worker Adjustment and Retraining Notification Act, requires employers with 100 or more employees to give 60 days' written notice before a plant closing or mass layoff. Several states have their own versions with lower thresholds or longer notice periods.
Key takeaways
- Federal WARN applies to employers with 100 or more full-time employees.
- A plant closing or mass layoff generally involves at least 50 employees at a single site.
- Notice goes to affected employees or their union, the state dislocated worker unit, and local government.
- Failing to give notice can cost up to 60 days of back pay and benefits per employee.
How WARN Act works
WARN is triggered by two kinds of events (US Department of Labor, WARN Act). A plant closing is the shutdown of a single site, or units within it, causing 50 or more employees to lose their jobs in a 30-day period. A mass layoff is a reduction at a single site affecting 500 or more employees, or 50 to 499 employees if they make up at least a third of the site's workforce. Losses in separate actions over 90 days can be added together.
Notice must go out 60 days before the first separation. Exceptions shorten notice in narrow situations: a faltering company seeking capital, unforeseeable business circumstances, or natural disasters. Employers that fall short can owe back pay and benefits for each day of the violation, up to 60 days, plus a civil penalty for failing to notify local government.
State laws can be stricter. New York and New Jersey require 90 days' notice, and New Jersey also requires mandatory severance. California's law reaches employers with 75 or more employees.
WARN Act example
A manufacturer with 420 employees plans to close one plant employing 85 people. That's a plant closing under federal WARN, so it sends written notices on March 1 for separations no earlier than April 30. Notices go to each employee, the state's dislocated worker unit, and the county's chief elected official. If the plant were in New York, the company would need 90 days' notice instead.
Why WARN Act matters for employers
WARN mistakes are expensive because damages multiply by headcount. A missed notice for 85 employees averaging $1,200 a week could cost about $870,000 in back pay alone, before benefits and penalties.
Layoffs are a regular part of the labor market: layoffs and discharges ran at about 1.6 million in August 2026 (BLS Job Openings and Labor Turnover Survey, August 2026). Before any reduction, count employees at each site across a 90-day window, check state mini-WARN laws, and plan notices, severance, and COBRA together. Our layoff notification email is a starting point for the employee message, not a substitute for the legal notice.
Common WARN Act mistakes to avoid
Counting only this month's layoffs
Separate actions within 90 days can be aggregated.
Forgetting remote employees
Remote workers are usually assigned to the site they report to or are managed from.
Overlooking state laws
State WARN laws often apply at lower thresholds and require longer notice.
Paying in lieu of notice without checking
Pay in lieu can reduce liability but doesn't satisfy every state law.
WARN Act: questions people also ask
Who must comply with the WARN Act?
How much notice does WARN require?
What is the penalty for violating WARN?
Does WARN apply to remote workers?
Do states have their own WARN laws?
Tools, templates, and guides for this topic
Where to go from here
See what helps
Get matched options
Three platforms for your size and states, with pricing ranges.
Start AI MatchGet free quotesHow we wrote this definition
HRTally glossary entries are written by people who have run US payroll, benefits, and HR operations, then checked line by line against primary sources such as the IRS, Department of Labor, EEOC, and Bureau of Labor Statistics. Dollar limits and rates are for 2026 unless stated. We review every entry at least twice a year and whenever a rule changes. This page explains general rules and isn't legal or tax advice; state law can differ. Read our editorial standards.
Sources
Cite this definition
Teachers, consultants, and HR communities are welcome to quote this definition with a link back to HRTally.
<blockquote>The WARN Act, or Worker Adjustment and Retraining Notification Act, requires employers with 100 or more employees to give 60 days' written notice before a plant closing or mass layoff. Several states have their own versions with lower thresholds or longer notice periods.</blockquote><p>Source: <a href="https://www.hrtally.com/hr-glossary/warn-act/">HRTally HR Glossary, WARN Act</a></p>
Written by the HRTally Research Team
Our guides are written and reviewed by people with hands-on US HR, payroll, and HR technology experience. Legal and tax facts are checked against primary sources, such as the Department of Labor, IRS, EEOC, and USCIS, and linked at the end of each guide. Vendors never review or pay for our editorial content.