What is the cost of offering health insurance to part-time employees?

The cost of offering health insurance to part-time employees varies widely based on your organization's size, industry, and plan design, but it commonly ranges from $4,000 to $7,000 per part-time employee annually for employer contributions. KFF's 2025 employer survey put the average single-coverage premium at $9,325, and employers that pay a reduced share for part-time staff, such as 50% to 75%, land within that range. Unlike full-time employees, part-time workers typically work fewer than 30 hours per week, and under the Affordable Care Act (ACA), employers with 50 or more full-time employees and full-time equivalents (FTEs) are only required to offer coverage to full-time employees. However, many companies choose to extend benefits to part-time staff as a competitive advantage for retention and engagement.

Several key factors drive the overall cost:

• Employer contribution strategy: Many employers contribute a lower percentage (e.g., 50% vs. 75% for full-time) or set a fixed dollar amount per part-time employee.
• Plan type: High-deductible health plans (HDHPs) paired with Health Savings Accounts (HSAs) carry lower premiums. In KFF's 2025 survey, HDHP/SO single premiums averaged $8,620 versus $9,818 for PPOs, about 12% lower.
• Eligibility thresholds: Some employers define part-time as 20-29 hours/week, while others use 15-29 hours, which can expand or shrink the risk pool.
• Administrative fees: Adding part-time employees to your benefits administration system, COBRA management, and compliance filings (e.g., ACA Form 1095-C) increases overhead by $100-$300 per employee annually.
• Wellness program integration: If you offer wellness incentives to part-time staff, additional costs may include biometric screenings, incentives, and program management fees.

ACA Compliance and Financial Penalties

If you have 50 or more full-time employees and full-time equivalents, offering coverage to part-time staff is optional. The ACA's employer mandate applies only to full-time employees, defined as averaging 30 or more hours of service per week, or 130 per month. Part-time workers sit outside the Section 4980H penalty calculation entirely: the IRS computes those penalties only against full-time employees, so a part-time employee who declines your offer and collects a Marketplace premium tax credit creates no penalty exposure. The Minimum Essential Coverage (MEC) and Minimum Value (MV) standards apply to the coverage you offer your full-time workforce; the 2026 penalty for a full-time employee who receives subsidized Marketplace coverage is $5,010 per year.

Hidden Costs to Watch For

• State and local rules: State mandates rarely reach part-timers. Massachusetts requires employers with 11 or more full-time-equivalent employees to make a fair and reasonable contribution toward full-time employees' coverage or pay an assessment; California has no state mandate for part-time coverage. Local rules differ: San Francisco's Health Care Security Ordinance requires employers with 20 or more workers to spend a minimum amount on healthcare for employees who work at least 8 hours per week.
• Risk pool and turnover: Part-time employees are often younger and healthier than full-time staff, which can lower claims costs if they participate. However, they may also have higher turnover, increasing administrative churn.
• Opt-in vs. opt-out: Only 30-50% of eligible part-time employees typically enroll, meaning you pay only for those who choose coverage. This can reduce total spending but create budgeting uncertainty.
• Direct vs. reimbursement models: Using an Individual Coverage Health Reimbursement Arrangement (ICHRA) instead of a group plan lets you set a fixed monthly allowance (e.g., $200-$400) that employees use to buy their own plans, capping your cost at a predictable amount per employee.

Variable-Hour Employees and the Look-Back Measurement Method

Part-time schedules are rarely static, and misclassifying a variable-hour worker is a costly compliance error. Under the ACA, a worker who averages 30 or more hours of service per week, or 130 per month, is full-time. For employees whose hours fluctuate, the IRS permits a look-back measurement method: you track hours over a measurement period of 3 to 12 months, and anyone who averages 30 or more hours per week is treated as full-time during the following stability period, even if their hours later fall below 30.

The exposure is real. A retailer or staffing firm that classifies someone as part-time without running a measurement period, and the employee later averages 30-plus hours and receives a Marketplace subsidy, can face the 2026 Section 4980H(b) penalty of $5,010 for that worker. Set the measurement and stability periods in advance, apply them consistently, and allow a short administrative period of up to 90 days for enrollment. If your part-time workforce is in retail, hospitality, or staffing, this is the piece of the cost equation a simple headcount model misses.

How to Calculate Your Specific Cost

To estimate your organization's expense, follow this framework:

1. Define eligibility: Decide on minimum hours (e.g., 20 hours/week) and waiting period (e.g., 90 days).
2. Choose a plan design: Select a benchmark plan (e.g., bronze or silver-level) and determine employer contribution (e.g., 50% of premium).
3. Estimate enrollment: Multiply your eligible part-time headcount by your predicted enrollment rate (e.g., 40% of eligible).
4. Total premium cost: Obtain quotes from carriers for your part-time group. For 10 part-time employees, a sample calculation: 10 employees × 40% enrollment = 4 enrolled × $500/month premium × 50% employer share = $1,000/month or $12,000 annually.
5. Add admin overhead: Include broker fees, benefits technology platform costs, and compliance support, typically 5-10% of premium.

Cost-Saving Strategies

• Offer a defined contribution HRA or ICHRA: This shifts risk to employees while capping your expense. For example, a $300/month allowance for part-time staff can cost less than a traditional group plan.
• Partner with a Professional Employer Organization (PEO): PEOs often provide access to large-group rates and consolidated administration, which can lower both premiums and overhead.
• Use tax advantages: Employer contributions are tax-deductible, and employees' contributions are pre-tax through Section 125 plans, which can reduce FICA payroll taxes by 7.65% for both employer and employee.
• Implement a waiting period: Delaying eligibility by 60-90 days reduces the number of part-time employees who ever enroll, especially for seasonal or transient workers.

Ultimately, the cost of offering health insurance to part-time employees is a strategic investment in workforce quality and retention. While the per-employee price tag may seem high, the return often includes lower turnover, increased productivity, and a stronger employer brand. Consider modeling costs with your broker or benefits consultant using your specific demographic data, and explore alternative funding models like level-funded plans or ICHRAs to balance budget predictability with competitive benefits.

This article is for general information only and is not legal, tax, or medical advice. Employers should consult their own advisors.