50 Is The Number. A business that has 50 or fewer full-time employees is not subject to a penalty for failing to provide affordable health insurance to its employees. So, now the questions – what is “full-time?” – full-time is defined as working thirty-hours a week (or more) on average during a one-month period. Part-time workers are counted up on an aggregate basis to determine whether the 50 full-time threshold is crossed (in general, dividing aggregate hours worked – if paid hourly — by 120) which is 4 weeks of 30 hours.