How do I calculate the total hours worked by all employees?

Include hours worked by salaried, hourly, part-time and seasonal workers, as well as hours worked by other workers subject to day to day supervision by your establishment (e.g., temporary help service workers).  Do not include vacation, sick leave, holidays, or any other non-work time, even if employees were paid for it.  If your establishment keeps records of only hours paid or if you have employees who are not paid by the hour please estimate the hours that the employees actually worked.