Separate ACA, COBRA, FMLA and retirement eligibility calculations. Use a growing-company example to identify obligations and prevent census errors.
June 22, 2026 · Financial Forte Staff
Historical article: prepared retrospectively using information available as of June 22, 2026.
A growing business may celebrate its fiftieth employee without realizing that different benefits rules count people in different ways. Conversely, an owner may assume the company is below an important threshold because only 49 people work full time. Both conclusions can miss the underlying calculation.
Review each obligation using its own counting method, measurement period and employer definition. Affordable Care Act employer status, federal COBRA and FMLA do not use one interchangeable headcount. A reliable census and coordinated review can reduce missed notices, unexpected costs and employee confusion as the business grows.
Separate the counts before deciding what applies
For Affordable Care Act applicable large employer status, the general test looks to the prior calendar year's average number of full-time employees plus full-time equivalents. Full time generally means at least 30 hours of service per week or 130 hours in a month. Non-full-time hours are combined under a separate calculation, capped at 120 hours per person for that purpose and divided by 120.[1]
Related employers may need to be aggregated, and exceptions can affect the result. Becoming an applicable large employer brings reporting and employer shared responsibility considerations. It does not mean every employee must receive identical coverage or that every employer automatically owes a payment. The coverage offered, affordability, minimum value and other conditions matter.[1]
Federal COBRA generally applies to private-sector group health plans sponsored by employers with at least 20 employees on more than half of the typical business days in the previous calendar year. Part-time employees count fractionally under COBRA's method. That calculation should not simply be replaced by the ACA full-time-equivalent formula.[2]
FMLA uses another framework. A private-sector employer generally becomes covered with at least 50 employees in 20 or more workweeks in the current or preceding calendar year. An employee's eligibility then involves additional conditions, including service, hours worked and the number of employees within 75 miles. Employer coverage and an individual's leave entitlement are separate questions.[3]
Work through a growing-company example
Suppose a company had 49 full-time employees and eight part-time employees in every month of 2025. Each part-time employee had 60 hours of service per month. Assume no relevant exception changes the calculation and that an adviser has checked whether related employers must be included.
The part-time group contributes 480 monthly hours to the ACA calculation: eight times 60. Dividing by 120 gives four full-time equivalents. Adding those four to the 49 full-time employees produces 53 for each month and therefore a 53 average for 2025. Under these assumptions, the company is an applicable large employer for 2026 even though only 49 people work full time.
For an FMLA employer-coverage review, the relevant population is 57 actual employees, not the ACA result of 53. If the applicable 20-workweek condition is met, the company must evaluate federal coverage on that basis. It still needs to check each requesting employee's eligibility, including the 12-month service requirement, 1,250 hours worked in the preceding 12 months and the 50-employees-within-75-miles condition.[3]
For COBRA, the 49 full-time employees alone would exceed 20 if present over the required prior-year business-day period. That does not turn a headcount spreadsheet into a complete continuation-coverage program. The employer still needs a process for qualifying events, notices, elections, premiums and coordination with its administrator. State continuation requirements may also require a separate review.[2]
The lesson is operational: labeling the company “under 50” could cause the team to miss an obligation before anyone realizes the label was built from the wrong population.
Keep retirement-plan eligibility on its own track
The same census should support retirement-plan administration, but the retirement plan's eligibility rules are not borrowed from health coverage thresholds. Service, age, entry dates, employee classifications and related employers can affect who must be considered. Long-term part-time employee rules add another reason to preserve reliable hours and service history.[4]
A payroll system may contain all the raw data while still producing the wrong report for a particular rule. Ask the administrator to specify the fields and definitions needed. Identify workers who changed schedules, transferred between related entities, returned after leave or were rehired. Those events are easy to miss in a year-end list of current employees.
For an ERISA plan, prudent administration and monitoring of service providers remain important fiduciary responsibilities. Assigning a vendor to calculate eligibility does not justify ignoring incomplete data or unresolved exceptions. Confirm who reviews the census, who approves the result and who ensures the resulting enrollment or notice task is completed.[5]
Build a threshold review into the growth process
Give HR, payroll, finance and the benefits adviser a shared timetable. Review the prior-year data early enough to address obligations that apply in the new year. When hiring accelerates or an acquisition is planned, perform a forward-looking review rather than waiting for the next annual renewal.
Retain the calculation, assumptions and advice received. A spreadsheet should show which rule it addresses, which period it measures and which entities it includes. A single total without those labels is easy to reuse incorrectly; keep separate outputs even when they begin with the same payroll data. Resolve ownership questions and unusual employee categories with the appropriate legal or tax adviser, then retain the written determination.
Before a new obligation takes effect, verify that the provider contract and payroll process can perform the required tasks. The employee benefit is straightforward: accurate administration helps people receive timely coverage information and leave or retirement-plan rights when applicable. The business benefit is fewer surprises, clearer vendor accountability and a more reliable estimate of the cost of growth.
Start with the latest hiring forecast and ask the benefits team which separate counts it changes. Require an answer by obligation, with an owner and date for the next action. That is more useful than waiting for the payroll roster to reach a memorable round number.
Related reading
Have more questions about employee headcount and benefits administration? Email Dave at dave@financialforte.com to discuss your questions and next steps.
The contact invitation is current; it does not imply this contact path existed on the historical reference date.
Educational information, not personalized investment, tax, legal or benefits advice. Examples use hypothetical assumptions. Verify current rules and your circumstances before acting.
Sources
- [1] IRS Publication 5208: Determining applicable large employer status — March 2018 revision
- [2] DOL FAQs on COBRA Continuation Health Coverage for Employers and Advisers — September 2025; DOL employee guide to health benefits under COBRA (Spanish edition) — September 2022
- [3] DOL Fact Sheet 28A: Employee Protections under FMLA — March 2025
- [4] IRS Notice 2024-73: Long-term, part-time employee guidance — Released October 3, 2024; applicable plan years after December 31, 2024
- [5] Meeting Your Fiduciary Responsibilities — September 2021
