weeknum() Function

Returns the week number within the year for the given date using a given methodology.


weeknum( date, [methodology] )

date: (Date) The date for which the week number will be determined.

methodology: (Integer) Controls what day is the first of the week with 1 correlating with the week beginning on Sunday and 2 correlating with the week beginning on Monday. The default value of methodology is 1.



1 is returned for any week that contains January 1st.


  • The last days of the year will return 1 if the first day of the next year is within the same calendar week. For example, the date December 31, 2021 is on a Friday, so this will return 1 because the date January 1, 2022 is on the Saturday of that week.


You can experiment with this function in the test box below.

Test Input

weeknum(date(2011,12,13)) returns 51

Open in Github Built: Fri, Mar 11, 2022 (04:59:07 PM)

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