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WEEKNUM Formula in Google Sheets (How to Use It in 2024)

WEEKNUM in Google Sheets

The WEEKNUM function in Google Sheets calculates the week number of a specific date within a year, indicating its numerical position from 1 to 52 or 53. This function is useful for analyzing data by week or tracking weekly activities.

WEEKNUM Formula in Google Sheets

The syntax for the WEEKNUM function is:

WEEKNUM(date, [type])

  • date: The date for which you want to find the week number. The date should be in a format recognized by Google Sheets (e.g., "2023-01-01", "1/1/2023", or a reference to a cell containing a date).

  • [type]: An optional argument specifying the week's start day and the counting system. By default, or when omitted, it is set to 1 which indicates that the week starts on Sunday. This adheres to the most common system in the United States. Other systems, for example, might start the week on Monday and use different rules for the first week of the year.

Here are the values you can use for the [type] argument:

  • 1 (or omitted): Week begins on Sunday.
  • 2: Week begins on Monday.
  • 11: Week begins on Monday, following the system used by the ISO 8601 date and time standard.

There are other numbers you can use for different starting days and counting systems, but 1, 2, and 11 are the most commonly used.

How to Use the WEEKNUM Function in Google Sheets

Follow the steps below to use the WEEKNUM function in Google Sheets. 

1. Select a Cell Next to a Date

Click on cell B2, right next to the first date in your dataset. This is where you'll enter the WEEKNUM formula to find the week number for the date in cell A2.

weeknum google sheets

2. Enter the WEEKNUM Formula

Type =WEEKNUM(A2) into cell B2. This formula calculates the week number for the date specified in cell A2.

google sheets weeknum

3. Specify the Date Using a Cell Reference

In this case, you're using the cell reference A2 in your formula to specify the date. This tells Google Sheets to use the date in cell A2 for the week number calculation.

weeknum in google sheets

4. Add the Type Argument (Optional) 

To have the week start on a different day, modify the formula by adding a comma and then the type number after A2. For instance, =WEEKNUM(A2, 2) sets the week to start on Monday. Skip this if you're fine with the default setting.

weeknum formula google sheets

5. Close the Formula and Press Enter

Press Enter after typing your formula. Cell B2 will display the week number corresponding to the date in A2.

weeknum function google sheets

6. Adjust the Formula as Needed

If you want to change which date you're calculating the week number for, simply edit the formula in the formula bar to reference the correct cell.

7. Copy the Formula for Multiple Dates

To find week numbers for all dates in your dataset, drag the fill handle from the bottom right corner of cell B2 down through column B. This action copies the formula to adjacent cells, adjusting the cell references automatically.

We hope that you now have a better understanding of what WEEKNUM in Google Sheets is and how to use the WEEKNUM formula in Google Sheets. If you enjoyed this article, you might also like our article on how to add arrows in Google Sheets or our article on MROUND in Google Sheets.

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