Human Resource Laws and Regulations: The Complete US Guide by Company Size

Federal employment law does not apply uniformly to every business. Which laws apply to you depends primarily on one number: how many employees you have. A company with 10 employees faces a different set of legal obligations than a company with 50, and both face different requirements than a company with 100.

Finding the answer is harder than it should be, because no single government resource lays this out clearly. The Department of Labor lists laws alphabetically. The EEOC explains what it enforces but not what other agencies enforce. State agencies cover state law but not federal.

This guide organizes every major US human resource law by the employee threshold at which it applies, so you can read your headcount and know which laws govern your business. It covers the 18 federal laws that matter most, the retention periods that come with them, the regulatory changes worth tracking, and how federal and state law interact when they conflict. If I had to name one place for a founder to start, it would be counting heads, because headcount decides most of what follows.

HR Laws at a Glance: Which Laws Apply to Your Business

This matrix is the reference you will come back to. It lists every major federal employment law, the employee count at which it takes effect, and the core compliance requirement. The thresholds are cumulative: a business with 50 employees must comply with every law at the 1+, 15+, 20+, and 50+ levels.

One note on counting: employee counts for most federal laws include all employees on payroll, not just full-time. Part-time employees count toward the threshold in most cases.

These thresholds are federal minimums. Many states apply anti-discrimination protections starting at 1 employee, require paid family leave regardless of company size, or mandate benefits that federal law does not require. Always check your state's requirements in addition to the matrix above.

The Three Most Important HR Laws

If you have to prioritize, start with three: the FLSA, Title VII, and the I-9 verification requirement under IRCA. Between them they govern how you pay people, how you decide who gets hired and promoted, and whether you documented the right to work for every person on payroll.

They come first because violations surface without anyone filing a complaint. Wage and hour problems turn up in a payroll audit, I-9 gaps turn up in an inspection, and both statutes bind you from your first employee. Title VII enters at 15, and it adds compensatory and punitive damages on top of back pay.

Anti-Discrimination Laws

Anti-discrimination laws form the largest category of federal employment regulation. They prohibit employment decisions based on protected characteristics and require employers to provide reasonable accommodations in certain circumstances.

EEO Laws and the Agency That Enforces Them

The EEO laws are the federal statutes guaranteeing equal employment opportunity, and the EEOC enforces all of them: Title VII, Title I of the ADA, the ADEA, the Equal Pay Act, GINA, the Pregnancy Discrimination Act, and the PWFA. Their thresholds differ, so a 16-person company is covered by most of them and still sits outside the ADEA.

Two of them get less planning than they deserve. GINA bars any use of genetic information or family medical history in employment decisions, which most often surfaces in wellness programs and post-offer medical questionnaires. The Pregnancy Discrimination Act sits inside Title VII, treating pregnancy as a sex-based protected characteristic, and the PWFA built the duty to accommodate on top of that floor.

Enforcement runs through a charge rather than straight to a courtroom. Every one of these statutes except the Equal Pay Act requires the worker to file a charge with the EEOC or a state fair employment agency before suing (EEOC).

Title VII of the Civil Rights Act (15+ employees)

Title VII prohibits discrimination based on race, color, religion, sex (including pregnancy, sexual orientation, and gender identity), and national origin. It covers every aspect of employment: hiring, firing, pay, promotions, training, and working conditions.

Title VII also prohibits retaliation against employees who file discrimination complaints or participate in investigations. Compliance requires posting EEO notices and maintaining hiring records for 1 year; in practice it also means having a process for handling discrimination complaints.

Americans with Disabilities Act (15+ employees)

The ADA prohibits discrimination against qualified individuals with disabilities and requires employers to provide reasonable accommodations unless doing so would cause undue hardship. A reasonable accommodation is any modification to the job, workplace, or work process that enables a qualified person with a disability to perform essential functions. Examples include modified schedules, ergonomic equipment, and restructured job duties.

When an employee asks, EEOC regulations say an informal interactive process (a conversation between employer and employee about possible accommodations) may be needed to find the right accommodation (29 CFR 1630.2(o)(3)).

Age Discrimination in Employment Act (20+ employees)

ADEA protects workers aged 40 and older from discrimination in hiring, firing, compensation, and terms of employment. It applies at the 20-employee threshold, which is different from the 15-employee threshold for Title VII and ADA. Mandatory retirement policies are prohibited for most positions.

Pregnant Workers Fairness Act (15+ employees)

The PWFA, effective since June 2023, requires employers to provide reasonable accommodations for known limitations related to pregnancy, childbirth, or related medical conditions. This is broader than the original Pregnancy Discrimination Act because it creates an affirmative right to accommodation, not just protection from discrimination.

Wage, Hour, and Classification Laws

The Fair Labor Standards Act is the foundational wage and hour law. It applies from your first employee and governs minimum wage, overtime pay at 1.5 times the regular rate for hours over 40 in a workweek, child labor restrictions, and recordkeeping.

The federal minimum wage has been $7.25 an hour since July 2009. According to the Department of Labor, 30 states plus the District of Columbia now set a higher rate, so for most employers the state figure is the one that governs (DOL).

The most consequential FLSA compliance issue for small businesses is employee classification: correctly identifying each worker as exempt or non-exempt from overtime requirements. Misclassification exposes the business to back pay claims for all unpaid overtime, liquidated damages equal to the back pay amount, and potential penalties.

The classification test examines job duties and salary level, not job title. Calling someone a "manager" does not make them exempt if their actual work does not meet the duties test.

The Equal Pay Act, which applies from employee one, requires equal pay for equal work regardless of sex. "Equal work" means jobs that require substantially equal skill, effort, and responsibility performed under similar working conditions. The statute permits pay differences based on seniority, merit, quantity or quality of production, or any factor other than sex (29 U.S.C. 206(d)).

Leave Laws

The Family and Medical Leave Act requires employers with 50 or more employees to provide up to 12 weeks of unpaid, job-protected leave per year for qualifying reasons: birth or placement of a child, serious health condition of the employee or an immediate family member, or qualifying exigencies related to military service.

Eligibility is a separate test. The employee needs 12 months of employment and 1,250 hours of service in the preceding 12 months, at a worksite where the employer has 50 or more employees within 75 miles (DOL).

FMLA is the federal floor. Many states run their own paid family and medical leave programs, which pay the leave, reach smaller employers, and cover more situations. Operating in several states means several leave rulebooks.

Paid family and medical leave programs have been enacted in 14 states and the District of Columbia. The Department of Labor Women's Bureau counts 13 states plus DC (DOL), and Virginia became the 14th when it enacted its program on April 22, 2026, with benefits starting December 1, 2028 (Code of Virginia).

USERRA (Uniformed Services Employment and Reemployment Rights Act) applies from employee one and requires employers to reemploy service members returning from military duty in the same position they would have held had they not been absent, with the same seniority, status, and pay. There is no minimum company size for USERRA.

Workplace Safety (OSHA)

The Occupational Safety and Health Act applies to virtually all private employers regardless of size. The General Duty Clause requires every employer to furnish a workplace "free from recognized hazards that are causing or are likely to cause death or serious physical harm" (OSH Act section 5). Beyond the general duty, specific OSHA standards apply depending on your industry.

Compliance essentials without a safety department: display the OSHA "Job Safety and Health" poster, maintain injury and illness records on OSHA Form 300, report workplace fatalities within 8 hours and hospitalizations within 24 hours, and provide the safety training your industry requires.

Small employers get a break on the paperwork. Employers with 10 or fewer employees are partially exempt from routine injury and illness recordkeeping (29 CFR 1904.1), and so are establishments classified in the low-hazard industry groups listed in the rule (29 CFR 1904.2). Neither exemption touches the duty to report a fatality or a severe injury.

Penalties escalate quickly. According to OSHA, a serious or other-than-serious violation carries a maximum penalty of $16,550, failure to abate costs $16,550 for each day past the abatement date, and a willful or repeated violation reaches $165,514 (OSHA).

Record retention for OSHA is among the longest of any federal requirement: injury and illness logs must be kept for 5 years, employee medical records for the duration of employment plus 30 years, and exposure records for at least 30 years (29 CFR 1910.1020).

Hiring and Immigration Laws

Every employer must verify employment eligibility using Form I-9 for every person hired, including US citizens. The employee signs Section 1 no later than their first day of work for pay, and you complete Section 2 within three business days of the start date (USCIS).

Keep each Form I-9 for 3 years from hire or 1 year after termination, whichever is later.

The penalty schedule runs on two tracks. A paperwork violation costs $288 to $2,861 for each individual it involves, while knowingly employing an unauthorized worker costs $716 to $5,724 per worker on a first order and $8,586 to $28,619 on a third or subsequent one (8 CFR 274a.10).

The Fair Credit Reporting Act (FCRA) governs background checks. Before running one, employers must provide a standalone written disclosure and obtain written permission from the candidate. An adverse decision then triggers a two-step process: a pre-adverse action notice with a copy of the report and the summary of rights, then a final notice naming the consumer reporting company (FTC).

Ban-the-box laws restrict when an employer may ask about criminal history. Most cover public hiring only, but several states reach private employers: the California Fair Chance Act starts at 5 employees (California Civil Rights Department), and Illinois bars the question until the applicant is found qualified and selected for an interview or, when there is no interview, until a conditional offer (Illinois DOL).

Benefits Compliance

COBRA requires employers with 20 or more employees to offer continuing health coverage to employees and dependents who lose coverage due to a qualifying event (termination, reduction in hours, divorce, death). Coverage runs 18 to 36 months depending on the event, and the plan may charge up to 102% of the premium, the full cost plus a 2% administrative fee (29 U.S.C. 1162).

The Affordable Care Act employer mandate applies at 50 full-time employees including full-time equivalents, averaged across the prior calendar year (IRS).

Applicable large employers must offer affordable minimum essential coverage to full-time employees or pay a penalty. Below that line the mandate does not apply, but QSEHRA (Qualified Small Employer Health Reimbursement Arrangement) can still reimburse employees for health costs.

ERISA governs employer-sponsored retirement and health plans. If you offer a 401(k), health plan, or other benefit plan, ERISA requires plan documentation, fiduciary responsibility, reporting and disclosure to participants, and a claims and appeals process. Supporting records are kept for 6 years (29 U.S.C. 1027).

Other Federal Laws You Should Know

The NLRA deserves special attention because it applies from your first employee and is often misunderstood. Section 7 protects the right of employees to engage in concerted activity for mutual aid or protection, which covers discussing pay and working conditions with each other (29 U.S.C. 157). A policy that forbids employees from discussing their pay is unlawful on a team of any size.

Regulatory Updates Employers Need to Track

Employment law changes constantly, especially at the state level. These are the developments that most directly affect small and growing businesses.

A newer category, not yet on most compliance checklists, is state-level menopause accommodation. Rhode Island amended its Fair Employment Practices Act on June 24, 2025 to extend its pregnancy accommodation framework to menopause and related conditions, with posting and individual notice obligations attached (Rhode Island Commission for Human Rights).

Illinois followed. The Menopause Equity and Care Act, Public Act 104-0793, amends the Illinois Human Rights Act so that refusing a reasonable accommodation for a menopause-related condition is a civil rights violation, effective January 1, 2027 (Illinois General Assembly).

No federal law specifically requires menopause accommodations at work. That makes this the kind of duty that arrives in one state where you happen to employ someone, with nothing in federal law to warn you it is coming.

The most actionable recommendation: review your state's employment law changes at the start of each year. State legislatures typically enact employment laws that take effect January 1 or July 1. Putting those dates into a compliance calendar is what turns the annual review into something that actually happens.

Federal vs State: How They Interact

The general rule is simple: when federal and state laws conflict, the law that provides greater protection to the employee applies. In practice, this means state law usually wins because states tend to set higher minimums and broader protections than federal law.

For businesses with employees in a single state, the compliance path is straightforward: apply the higher standard between federal and state law for each requirement. For multi-state employers, each state's laws apply to employees working in that state. A clear employee handbook that references applicable state-specific policies is the simplest way to document compliance across states.

Record Retention Schedule

Different laws require different retention periods. The EEOC rule is the shortest: an employer with 15 or more employees keeps every personnel and employment record for one year from the date the record was made or the personnel action was taken, whichever is later (29 CFR 1602.14).

Missing records during an audit or investigation work against the employer. In a wage claim where the employer's records are inadequate, the Supreme Court lets the employee prove hours worked by reasonable inference, and the employer then carries the burden of rebutting that estimate (Anderson v. Mt. Clemens Pottery). The schedule below is the full picture.

The practical rule for businesses without a dedicated HR department: retain all employee records for at least 7 years after termination. This single policy covers nearly all federal requirements and most state requirements. Digitizing records through a document management system eliminates the storage problem and makes retrieval during audits straightforward.

HR Compliance Checklist

If you do not have a dedicated HR person, this checklist covers the compliance fundamentals that apply to most businesses. Check the items that apply at your employee count using the threshold matrix above.

A platform like FirstHR handles the document collection, e-signature, and storage pieces of this checklist. Form I-9 and W-4 go on the new hire's first-day list as tasks, and completed forms are kept in their employee file (the forms themselves are completed outside the platform). Handbook acknowledgments are e-signed, and training completions are recorded with a signature.

Frequently Asked Questions