Under the Age Discrimination in Employment Act, the number of employees that triggers coverage for a private employer is 20. More precisely, a private business is covered if it has at least 20 employees on each working day in 20 or more calendar weeks during the current or preceding calendar year.1Office of the Law Revision Counsel. 29 USC 630 – Definitions Fall below that line and the federal statute does not reach your employer, though state law often does.
The 20-Employee, 20-Week Rule
The threshold has two parts, and both have to be satisfied. The employer needs 20 employees on each working day, and it needs to hit that count during at least 20 calendar weeks. Those 20 weeks do not have to run back-to-back. A business that staffs up for two busy seasons and dips below 20 in between still qualifies as long as the qualifying weeks add up to 20 across the year.
The rule also looks backward. Coverage attaches based on either the current calendar year or the preceding one, so a company that recently downsized can remain subject to the ADEA on the strength of last year’s headcount. A growing business works the other direction: once it has hit 20 employees for 20 weeks, it is covered going forward.
How Employees Are Counted
The Supreme Court endorsed the EEOC’s payroll method for counting employees in its 1997 decision in Walters v. Metropolitan Educational Enterprises.2U.S. Equal Employment Opportunity Commission. Selected Supreme Court Decisions 1971-1999 Under that approach, anyone who has an employment relationship with the company on a given day counts, whether or not they physically worked or logged hours that day. A worker on vacation, out sick, or on temporary layoff still counts.
In practice, the EEOC looks at whether a person appears on the employer’s payroll for a given week. If someone maintained an employment relationship for at least 20 calendar weeks in the relevant year, that person generally counts toward the total.3U.S. Equal Employment Opportunity Commission. How Do You Count the Number of Employees an Employer Has? Payroll tax records like Form 941 and internal staffing reports are the usual verification sources during an investigation.
Part-Time and Seasonal Workers
Full-time, part-time, and seasonal employees all count. There is no minimum-hours requirement. A part-time worker who shows up for one shift a week is counted the same as a full-time salaried manager for jurisdictional purposes.3U.S. Equal Employment Opportunity Commission. How Do You Count the Number of Employees an Employer Has?
Independent Contractors
Independent contractors do not count. The distinction comes down to how much control the employer exercises over the worker. Courts look at who sets the schedule, who provides tools and equipment, where the work happens, and whether the worker can take on other clients. An employer that controls the details of how work gets done is more likely to have an employment relationship, regardless of what the contract calls the arrangement. Misclassifying employees as contractors can backfire two ways: it can push a company over the 20-employee threshold it thought it was under, and it can create back-pay exposure for the misclassified workers themselves.
Partners, Directors, and Shareholders
Whether someone with a partner or shareholder-director title counts as an employee turns on the economic reality of the role. The Supreme Court’s Clackamas decision set out six factors: whether the organization can hire or fire the individual, whether it supervises their work, whether they report to someone above them, how much influence they have over the organization, whether written agreements treat them as employees, and whether they share in profits and losses. A “partner” who actually functions like a supervised employee can still count. Substance controls, not the label.
U.S. Citizens Working Abroad
The ADEA’s definition of employee includes U.S. citizens working outside the country for American employers or for foreign companies controlled by American employers. Those overseas workers count toward the employee total and are themselves protected.
Who Is Not an Employee at All
The statute carves out elected officials, their personal staff, appointees at the policymaking level, and immediate advisers to those officials. Government workers covered by civil service rules remain protected even when they work in an elected official’s office.1Office of the Law Revision Counsel. 29 USC 630 – Definitions
When Separate Entities Get Combined
Some employers split operations across multiple entities, each with fewer than 20 workers. Courts see through that structure using the integrated enterprise test, which asks whether nominally separate businesses actually function as a single employer. The analysis weighs four factors: how interrelated the operations are, whether management is shared, whether labor relations decisions are centralized, and whether there is common ownership or financial control. No single factor is decisive, though courts tend to focus most heavily on the first three, because those reveal whether the entities operate independently in any real sense.
A shared human resources department making hiring and firing decisions across entities is a common red flag. If two businesses share HR, use the same payroll system, and have overlapping leadership, a court is likely to combine their headcounts. That prevents a company of 50 from creating three LLCs of 16 or 17 people each to slide under the threshold.
Covered Employers Beyond Private Companies
The 20-employee rule is a private-sector rule. Other categories of employers are covered on different terms.
- State and local governments are added as covered employers in a separate clause, without the 20-employee qualifier. The EEOC lists them as a distinct covered category.4U.S. Equal Employment Opportunity Commission. Fact Sheet: Age Discrimination
- Federal agencies, military departments, the Postal Service, and several other federal entities are covered under a separate provision of the ADEA that prohibits age discrimination in federal personnel actions. No employee count applies.5Office of the Law Revision Counsel. 29 USC 633a – Nondiscrimination on Account of Age in Federal Government Employment
- Employment agencies are covered if they regularly find workers for covered employers, regardless of the agency’s own staff size.1Office of the Law Revision Counsel. 29 USC 630 – Definitions
- Labor organizations are covered if they operate a hiring hall or have at least 25 members and meet certain representational criteria.1Office of the Law Revision Counsel. 29 USC 630 – Definitions
Indian tribes sit in a different position. The ADEA does not explicitly exempt tribal employers, but multiple federal circuits have held that tribal sovereign immunity shields tribes from ADEA suits unless Congress has clearly overridden that immunity or the tribe has waived it, and courts have found no such clear override in the statute’s text.
If the Employer Has Fewer Than 20
Federal law will not reach an employer under the 20-employee threshold, but state law often does. Many states have their own age discrimination statutes with much lower thresholds. Several set the bar at one employee, others at five. State statutes also frequently protect workers under 40, extending beyond the federal age floor.
State claims typically go through a state human rights commission or civil rights agency, and filing fees at those agencies are generally zero. Remedies vary by state, but commonly include back pay, reinstatement, and in some jurisdictions compensatory damages that the ADEA itself does not authorize. If your employer is small and you think you were treated differently because of your age, the state labor or civil rights agency is the right first stop.