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WorksheetFunction.WeekNum method (Excel)

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Returns a number that indicates where the week falls numerically within a year.

Syntax

expression.WeekNum (Arg1, Arg2)

expression A variable that represents a WorksheetFunction object.

Parameters

Name Required/Optional Data type Description
Arg1 Required Variant Serial_num - a date within the week. Dates should be entered by using the DATE function, or as results of other formulas or functions. For example, use DATE(2008,5,23) for the 23rd day of May, 2008. Problems can occur if dates are entered as text.
Arg2 Optional Variant Return_type - a number that determines on which day the week begins. The default is 1.

Return value

Double

Remarks

Important

The WeekNum function considers the week containing January 1 to be the first week of the year. However, there is a European standard that defines the first week as the one with the majority of days (four or more) falling in the new year. This means that for years in which there are three days or less in the first week of January, the WeekNum function returns week numbers that are incorrect according to the European standard.

The following table represents possible values for Arg2.

Return_type Week begins
1 Week begins on Sunday. Weekdays are numbered 1 through 7.
2 Week begins on Monday. Weekdays are numbered 1 through 7.

Microsoft Excel stores dates as sequential serial numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900. Microsoft Excel for the Macintosh uses a different date system as its default.

Note

Visual Basic for Applications (VBA) calculates serial dates differently than Excel. In VBA, serial number 1 is December 31, 1899, rather than January 1, 1900.

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