There is no minimum headcount to start forming a union at a private-sector workplace. Two coworkers talking about pay or safety are already protected by federal law. To trigger a formal NLRB election, organizers need signed authorization cards from at least 30 percent of the workers in the proposed bargaining unit, and to win that election the union needs a majority of the votes actually cast. Everything else about how many employees are needed to form a union follows from those three numbers: two, 30 percent, and 50-percent-plus-one of the ballots.
Two Coworkers Are Enough to Be Protected
Organizing rights kick in long before anyone files paperwork. Section 7 of the National Labor Relations Act protects employees who engage in concerted activities for mutual aid or protection.1National Labor Relations Board. Interfering With Employee Rights (Section 7 and 8(a)(1)) Two coworkers discussing low wages, circulating a letter about unsafe conditions, or jointly refusing to work in dangerous heat are all covered. An employer who fires, demotes, or disciplines them for it commits an unfair labor practice.
Even one employee can be protected if they raise a complaint on behalf of the group, try to get coworkers to act together, or prepare for group action.2National Labor Relations Board. Concerted Activity The Supreme Court read this broadly in NLRB v. Washington Aluminum Co., holding that unorganized workers who walked off the job over a freezing workplace didn’t need a union, a vote, or even a formal demand. Acting together was enough.3Cornell Law School. NLRB v. Washington Aluminum Co.
One boundary worth flagging: the NLRA covers private-sector employees. Government workers at every level, agricultural laborers, domestic workers, independent contractors, anyone employed by a parent or spouse, and workers in the airline and railroad industries are outside the Act.4National Labor Relations Board. Are You Covered? Public-sector workers may have organizing rights under separate federal or state statutes, but coverage varies by jurisdiction and occupation.
30 Percent to File an Election Petition
Turning informal collective action into a certified union means filing a petition with the NLRB, and that petition needs documented support from at least 30 percent of the employees in the proposed bargaining unit.5National Labor Relations Board. Conduct Elections Workers show that support by signing authorization cards stating they want a specific union to represent them. The petition itself is filed on Form NLRB-502 (RC), typically through the Board’s regional office.6National Labor Relations Board. RC Petition
The math is straightforward. A 60-person unit needs 18 signed cards. A 200-person unit needs 60. Fall below 30 percent and the regional director will dismiss the petition without further investigation. Experienced organizers rarely stop at the floor. Most aim for signatures from 60 to 70 percent of the unit, because signers change their minds, face pressure, or don’t show up on election day.
Cards should be dated. No formal regulation sets an explicit expiration, but the Board’s longstanding practice treats cards as stale after roughly a year. Undated or clearly outdated cards can be challenged during the investigation, and if enough are thrown out, support can drop below the 30 percent line.
Who Counts in the Bargaining Unit
The 30 percent figure only means something once you know which employees are in the denominator, and that definition is one of the most contested pieces of any campaign. The NLRB applies a “community of interest” test, weighing whether proposed unit members share similar job duties, supervision, working conditions, pay structures, and regular contact.7National Labor Relations Board. Board Modifies Framework for Appropriate Bargaining Unit Standard A single warehouse with one set of managers is simple. A multi-location employer with several departments gets complicated quickly.
Employers generally want a larger unit, which dilutes support; unions often propose a smaller unit where support is strongest. Under the current standard restored in American Steel Construction, Inc. (2022), the petitioned-for unit is presumptively appropriate so long as its members are readily identifiable as a group sharing a community of interest. An employer that wants to sweep in additional workers must prove those excluded employees share an “overwhelming community of interest” with the proposed group.7National Labor Relations Board. Board Modifies Framework for Appropriate Bargaining Unit Standard
Some categories are excluded from any unit by law. Supervisors with authority to hire, fire, discipline, or use independent judgment over other employees cannot be in the unit, and neither can managers or confidential employees who handle labor relations information.8National Labor Relations Board. National Labor Relations Act – Section: DEFINITIONS Payroll records settle the final count of eligible workers once the unit is agreed on or decided after a hearing.
Winning: Majority of the Votes Cast
Once the petition is validated and the unit is set, the Board schedules a secret-ballot election. The union wins on a majority of the votes actually cast, not a majority of eligible employees.5National Labor Relations Board. Conduct Elections If 100 workers are eligible but only 40 vote, 21 “yes” ballots carry the election. A tie means the union loses and the status quo continues.
This is where the gap between card-signing and election results bites. Workers who signed cards months earlier may have changed their minds, faced management pressure, or skipped the vote. The 30 percent showing of interest is a floor for filing; the real campaign is convincing a majority of whoever walks into the voting booth.
Once the election is directed, the employer has five business days to hand over a voter eligibility list, sometimes called an Excelsior list, with names, work locations, shifts, and job classifications of all eligible voters.9Federal Register. Representation-Case Procedures: Voter List Contact Information Regional directors then set the election for the earliest practicable date, with no mandatory waiting period.10National Labor Relations Board. NLRB Fact Sheet – Representation Case Procedures A win produces a formal certification, and the employer is then required to bargain in good faith with the union as the exclusive representative of the unit.5National Labor Relations Board. Conduct Elections
Majority of Cards: Voluntary Recognition Without an Election
An election isn’t the only route. If a union collects authorization cards from a majority of the bargaining unit, meaning more than 50 percent rather than the 30 percent floor for a petition, it can ask the employer to recognize the union voluntarily. Under the Board’s 2023 Cemex Construction Materials Pacific, LLC decision, an employer presented with majority card support must either recognize the union or promptly file an RM petition asking for an election.11National Labor Relations Board. Board Issues Decision Announcing New Framework for Union Representation Proceedings
The Cemex framework also raised the stakes for employer misconduct. If the employer chooses the election route and then commits unfair labor practices serious enough to taint the results, the Board will not simply rerun the election. It will dismiss the employer’s petition and order recognition and bargaining with the union.11National Labor Relations Board. Board Issues Decision Announcing New Framework for Union Representation Proceedings
The Same Numbers Apply to Decertifying a Union
Workers who want to remove an existing union face the same numerical thresholds. Decertification requires signatures from at least 30 percent of the bargaining unit on an RD petition filed with the NLRB.12National Labor Relations Board. Decertification Petitions – RD The Board runs a secret-ballot election, and a majority of the votes cast against continued representation removes the union.
Timing is the catch. Federal law bars any new election in a unit for 12 months after a valid one, and while a collective bargaining agreement is in effect the Board will not process petitions for up to three years of the contract’s term. The window opens between 90 and 60 days before the agreement expires, or 120 and 90 days for healthcare institutions.13National Labor Relations Board. National Labor Relations Board Retains Longstanding Contract-Bar Doctrine14Federal Register. Representation-Case Procedures: Election Bars Miss the window and organizers wait for the next one.
Employers cannot initiate or assist a decertification effort. The push has to come from employees themselves, and management involvement in circulating the petition or funding the campaign can trigger unfair labor practice charges that block the whole process.