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WEEKNUM function in Google Sheets

Returns a number representing the week of the year where the provided date falls.

=WEEKNUM(date, [type])

WEEKNUM syntax and parameters

Two arguments, one required.

  • dateanyRequired

    The date for which to determine the week number. Must be a reference to a cell containing a date, a function returning a date type, or a number.

  • typenumberOptional

    [ OPTIONAL - default is 1 ] - A number representing the day that a week starts on as well as the system used for determining the first week of the year (1=Sunday, 2=Monday).

WEEKNUM examples

Formulas you'll actually reuse.

  1. The calendar week of an invoice date (week 1 holds 1 January, weeks start Sunday):

    =WEEKNUM(B2)

    Result33

  2. 1 January is always week 1 here — unlike ISOWEEKNUM, which gives 53:

    =WEEKNUM(DATE(2027, 1, 1))

    Result1

WEEKNUM in Excel

Same name — your formula ports as-is.

Try WEEKNUM in the playground

Edit the example — nothing to install.

Preloaded with the WEEKNUM formula from Example 1 — change anything and watch it respond.

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Related functions

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