How to Use WEEKNUM Function

The WEEKNUM Function is to return the week number with the date you specified.


= WEEKNUM(serial_number,[return_type])


  • Serial_number is required. A date within the week which you are looking for. Serial number should be a date in Microsoft Excel format, the function will return to an error when it is in a wrong format, such as text format.
  • Return_type is optional. A number that determines on which day the week begins, default is 1.


By default, Microsoft Excel uses January 1, 1900 as serial number 1. If a serial number or return type is out of the range, the result will return "#NUM!" error.

Download: WEEKNUM Function

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