WORKDAY(S, D[, H])

Description
Returns the serial day value that is D working days after day S (if D is positive) or D working days before day S (if D is negative), excluding weekends and all holidays specified as dates in range H.

Parameters
S
Serial start date value

D
Number of days before (negative) or after (positive) start date

H
Cell or range of cells containing serial date values to exclude

Examples
WORKDAY(DATE(91, 1, 1), 5, B1..B2) = 33249 or 01/11/91
where A1..A2 =
DATEVALUE("1/7/91"),
DATEVALUE("1/8/91")

WORKDAY(DATE(93, 1, 1), 258, A1..A5) = 34334 (or 12/31/91)
where A1..A5 =
DATEVALUE("1/1/93"),
DATEVALUE("5/25/93"),
DATEVALUE("7/4/93"),
DATEVALUE("9/3/93"),
DATEVALUE("11/28/93")