Write down the starting date. This is often the start of a new budget period (first of the month) or the date in which you receive a time-sensitive document (such as a lawsuit in which you have a certain number of days to respond).
Write down an ending date or the number of workdays you have before a deadline (such as if a paper must be sent within ten business days).
Open a calendar for the current year that encompasses the start date and the end date.
Count all days Monday through Friday. Exclude holidays and weekends. Begin your count on the first business day (Monday through Friday excluding holidays) after the start date. End on the ending date or upon reaching the time limit.
For example, assume on Tuesday, June 1, 2010, a friend offers you his car for a great price but tells you that you must accept the offer within ten workdays. Start counting days from June 2 (Wednesday). You have until June 15 to answer (ten business days).