How do you calculate FTEs?

You calculate the number of hours a person or group of people work on their activities and then divide that number by the total possible work hours for 1 individual. The total possible work hours equals either 1. 40 hr/wk * 52 wks = 2080 hours or 2. 40 hr/wk * 4 wks * 12 months = 1920. Either equation is acceptable.