The National Taxpayer Advocate has a TAS-ESRP Estimator for determining the number of full-time and full-time equivalent employees, whether you may be an applicable large employer (subject to the employer mandate under the Affordable Care Act), and an estimate of the maximum penalty you’d paid if you don’t provide affordable coverage to full-timers. Check the information you need (e.g., each employee’s hours of service for each month) in order to use the estimator.