/text/scalc/01/func_weeknumadd.xhp WEEKNUM_ADD function WEEKNUM_ADD The result indicates the number of the calendar week for a date. The WEEKNUM_ADD function is designed to calculate week numbers exactly as Microsoft Excel does. Use the WEEKNUM function, or format your date cells using the WW formatting code, when you need ISO 8601 week numbers. Syntax WEEKNUM_ADD(Date; ReturnType) Date is the date within the calendar week. ReturnType is 1 for week beginning on a Sunday, 2 for week beginning on a Monday. Example In which week number does 12.24.2001 fall? =WEEKNUM_ADD(24.12.2001;1) returns 52.