WorksheetFunction.WeekNum Method

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

Namespace:  Microsoft.Office.Interop.Excel
Assembly:  Microsoft.Office.Interop.Excel (in Microsoft.Office.Interop.Excel.dll)

Syntax

'Declaration
Function WeekNum ( _
    Arg1 As Object, _
    Arg2 As Object _
) As Double
'Usage
Dim instance As WorksheetFunction
Dim Arg1 As Object
Dim Arg2 As Object
Dim returnValue As Double

returnValue = instance.WeekNum(Arg1, Arg2)
double WeekNum(
    Object Arg1,
    Object Arg2
)

Parameters

  • Arg1
    Type: System.Object

    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
    Type: System.Object

    Return_type - a number that determines on which day the week begins. The default is 1.

Return Value

Type: System.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.

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.

See Also

Reference

WorksheetFunction Interface

WorksheetFunction Members

Microsoft.Office.Interop.Excel Namespace