The Excel function: WORKDAY
Returns a number that represents a date that is the indicated number of working days before or after a date (the starting date). Working days exclude weekends and any dates identified as holidays. Use WORKDAY to exclude weekends or holidays when you calculate invoice due dates, expected delivery times, or the number of days of work performed.
Tip To calculate the serial number of the date before or after a specified number of workdays by using parameters to indicate which and how many days are weekend days, use the WORKDAY.INTL function.