ACA Hours Tracking: How to Count Full-Time Employees and Measure Hours for Form 1095-C

By Nicole Hullihen, former SaaS Chief Operating Officer and Microsoft MVP · Updated November 1, 2026

The Affordable Care Act's employer rules all come back to one thing: hours. Whether you're an applicable large employer, which employees count as full-time, who must be offered coverage and what goes on each employee's Form 1095-C all depend on accurate hours. Year-end is when many businesses discover their hour records don't line up with what they need to report.

This guide explains the ACA hour rules, how to count full-time and full-time equivalent employees, the two ways to measure hours and what records you need, with a free ACA hours tracker. ACA rules are detailed and change over time, so confirm details with the IRS, your benefits broker or a tax advisor.

The Key Numbers

What Counts as an Hour of Service?

The IRS defines an hour of service as each hour an employee is paid, or entitled to be paid, for performing duties for the employer, plus each hour the employee is paid or entitled to be paid for time when no duties are performed, such as vacation, holiday or illness. That means ACA hours aren't just hours worked.

Your time clock records hours worked, and your PTO system records paid leave. You need both to count hours of service correctly. See PTO accrual.

Step 1: Determine Whether You Are an ALE

You're an applicable large employer for the current year if you had at least 50 full-time employees, including full-time equivalent employees, on average during the prior calendar year. To figure it out, count each month of last year:

1. Count employees with 130 or more hours of service in the month as full-time.
2. Add the hours of service of all other employees for the month, counting no more than 120 hours for any one employee.
3. Divide that total by 120 to get full-time equivalents for the month.
4. Add full-time employees and FTEs for the month.
5. Add the 12 monthly totals and divide by 12.

Related companies under common ownership may have to be combined. Ask your tax advisor. See how to calculate FTE.

Free ACA Hours Tracker

Enter hours of service (hours worked plus paid leave) for each employee each month.

Step 2: Choose How to Measure Full-Time Status

ALEs need to know which employees are full-time each month. The IRS allows two methods.

Monthly Measurement Method

You look at each employee's hours of service each calendar month. If they have 130 or more, they're full-time for that month. It's simple and works well when hours are steady, but status can change month to month for employees whose hours vary, which makes offering coverage harder to manage.

Look-Back Measurement Method

You measure an employee's hours over a past period, called a measurement period, and use the average to set their status for a future period, called a stability period, during which status doesn't change even if hours do. An administrative period between the two gives you time to determine status and handle enrollment. The IRS rules set limits on how long each period can be and require consistent treatment for categories of employees. This method is common for employers with variable-hour, part-time or seasonal staff. Work with your benefits advisor to set up the periods correctly.

Note that the look-back method can't be used when determining whether you're an ALE in the first place; that count uses monthly hours.

Variable-Hour and Seasonal Employees

Employees whose hours swing from week to week, such as restaurant servers, retail workers or on-call staff, are where ACA tracking gets hard. A server who works 25 hours in slow months and 38 in busy months might be full-time some months and not others. The look-back method was designed for these situations. Track their hours carefully, and don't rely on the hours you scheduled; use hours actually recorded.

Seasonal workers who work only during a specific time each year may be handled differently under the measurement rules. See the seasonal hiring guide and part-time employee hours.

Step 3: Track Hours Every Month

• Record hours worked with a reliable time clock, not estimates.
• Add paid leave hours from your PTO records.
• Total hours of service by employee each month.
• Flag employees near 130 hours, especially new or variable-hour staff.
• Store monthly totals where you can find them at year-end.

Small differences matter. An employee with 128 hours in a month is not full-time for that month; one with 131 is. Accurate time records are the only way to know.

Hours for Salaried Employees

Salaried employees often don't clock in, but you still need hours of service for ACA purposes. IRS rules allow certain methods for employees not paid hourly, including counting actual hours or using equivalencies, such as crediting a set number of hours per day or week worked, as long as the method doesn't substantially understate hours. Most full-time salaried employees are clearly full-time, but check with your advisor on the method you use.

Step 4: Use Hours for Forms 1094-C and 1095-C

ALEs file Form 1094-C and a Form 1095-C for each full-time employee, reporting offers of coverage month by month. The monthly full-time status from your hours tracking drives what goes on each form. Check the current IRS instructions for Forms 1094-C and 1095-C for due dates and how forms must be provided to employees, since filing rules have changed in recent years.

Records to Keep

• Time records showing hours worked.
• PTO, holiday and paid leave records.
• Monthly hours of service totals.
• Measurement method and period definitions.
• Offers of coverage and employee responses.
• Copies of filed forms.

See how to track employee hours.

Businesses Near 50 Employees

If you're growing toward 50, track full-time and FTE counts every month, not just at year-end. Adding part-time staff adds FTEs, so a business with 42 full-time employees and a large part-time crew can cross the line. Knowing your count early gives you time to plan benefits and budgets for the year you become an ALE. See strategic workforce planning.

Example: A Restaurant Group

A restaurant group with three locations had 31 full-time managers and cooks and about 70 part-time servers and hosts. The owner assumed they were well under 50. Their accountant asked for monthly hours of service. Part-time employees averaged about 2,400 hours a month, or 20 FTEs, putting the group at 51 on average. Because it was close, the owner set up monthly ACA hour reports from the time clock, worked with a broker on coverage and adopted a look-back method for the variable-hour servers.

Common Mistakes

• Counting only hours worked and leaving out paid leave.
• Using scheduled hours instead of actual hours.
• Ignoring part-time employees when counting FTEs.
• Not tracking monthly until year-end.
• Inconsistent measurement periods across similar employees.
• No hours for salaried staff.
• Assuming you're under 50 without doing the math.

ACA Hours Checklist

New Hires and ACA Status

When you hire someone, decide right away how you'll treat them under your measurement method. An employee hired into a job that is reasonably expected to be full-time is generally treated differently from a variable-hour or seasonal hire. Document the expected hours and classification in the hire record, and start tracking hours of service from the first day. Getting this right at hiring avoids surprises when the first measurement period ends. See new hire reporting.

Monthly ACA Hours Report

A simple monthly report keeps you ahead of year-end. Run it a few days after each month ends, once timesheets and PTO are final:

Save each month's report. At year-end, you'll have twelve months of hours of service ready for your forms and your advisor.

Rehired and Returning Employees

Employees who leave and come back, including seasonal workers who return each year, can be tricky. IRS rules address whether a returning employee is treated as new or as continuing, depending on how long they were gone. Keep accurate termination and rehire dates, and ask your advisor how your measurement method handles returning employees.

Working With Your Payroll Provider or Broker

Many payroll providers and benefits brokers help with ACA reporting, but they rely on the hours you give them. If hours of service are missing paid leave or include estimated rather than actual hours, the forms will be wrong. Before year-end, confirm with your provider what hours data they need, which pay codes count as hours of service and who is responsible for preparing and filing Forms 1094-C and 1095-C.

Year-End ACA Timeline

Check the current IRS instructions for exact deadlines each year. See the end-of-year checklist.

Part-Time Employees Who Pick Up Extra Shifts

A part-time employee scheduled for 24 hours a week who picks up extra shifts during busy months can cross 130 hours of service without anyone noticing. Under the monthly method, that makes them full-time for the month. Under a look-back method, those extra hours raise their average for the measurement period. Watch for part-time employees whose actual hours are creeping up, and review open-shift pickups and overtime with your ACA status in mind. The time clock, not the schedule, is the record that counts. Run a quick report each month of part-time employees over 110 hours so you can see who is getting close before they cross the line.

Keeping ACA Records Organized

Store monthly hours reports, measurement method documents and offer records together by year, so you can answer IRS questions quickly if they come.

Final Thoughts

ACA compliance runs on hours. Track hours worked and paid leave for every employee every month, count full-time and full-time equivalent employees to know whether you're an applicable large employer, choose a measurement method that fits your workforce and keep records that support your forms. When your time and PTO records are accurate, year-end ACA reporting becomes a report you run, not a scramble to reconstruct the year.

Track ACA Hours With Updoot

Updoot's employee time clock records actual hours worked for every employee, PTO tracking records paid leave and the payroll report totals hours by employee for any month, giving you the hours of service you need to count full-time employees and prepare ACA forms.

Sources

• IRS: Identifying Full-Time Employees
• IRS: Determining if an Employer Is an Applicable Large Employer

Frequently Asked Questions