Date & Time
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=WEEKNUM()
Returns the week number of a specific date. For example, the week containing January 1 is the first week of the year, and is numbered week 1. There are two systems used for this function:
Applies To:
Excel for Microsoft 365Excel for Microsoft 365 for MacExcel 2024Excel 2024 for MacExcel 2021Excel 2021 for MacExcel 2019Excel 2016
=WEEKNUM(serial_number,[return_type])
Hover argument names in the table for details.
Output typeNumber
Popularity35 / 100
VolatileNo
Dynamic ArrayNo
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◧ Arguments
| Argument | Type | Required | Description |
|---|---|---|---|
serial_number |
Date | Required | 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. |
return_type |
Number | Optional | A number that determines on which day the week begins. The default is 1. 1 or omitted = Sunday; 2 = Monday; 11 = Monday; 12 = Tuesday; 13 = Wednesday; 14 = Thursday; 15 = Friday; 16 = Saturday; 17 = Sunday; 21 = Monday. |
▣ Examples
▦ Data
| Cell | Value |
|---|---|
A2 |
3/9/2012 |
A3 |
3/9/2012 |
Number of the week in the year that 3/9/2012 occurs, based on weeks beginning on Sunday (default).
=WEEKNUM(A2)
Result:
10
Number of the week in the year that 3/9/2012 occurs, based on a week beginning on Monday (the second argument, 2).
=WEEKNUM(A2,2)
Result:
11
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