ISOWEEKNUM

ISOWEEKNUM(date)

Returns the number of the ISO week of the year for a given date.

date

The date.

REMARKS

* This function was added in Excel 2013.
* This function returns a number between 1 and 54.
* The week number returned is according to the European ISO standard. All weeks start on a Monday and week number 1 is assigned to the first week that contains a Thursday.
* If "date" is not a valid date, then #VALUE is returned.
* If "date" is not a valid number, then #NUM is returned.
* You can use the NOW function to return the serial number of the current system date and time.
* You can use the TODAY function to return the serial number of the current system date.
* You can use the WEEKNUM function to return the week number in the year for a given date.
* For the Microsoft documentation refer to support.microsoft.com
* For the Google documentation refer to support.google.com

	A
1	=TODAY() = Monday, May 22, 2023
2	=NOW() = Monday, May 22, 2023, 09:50
3	=WEEKNUM(A1,21) = 21
4	=ISOWEEKNUM(A1) = 21
5	=ISOWEEKNUM(A1+7) = 22
6	=ISOWEEKNUM(A2+14) = 23

1 - What is the current system date. This cell has been formatted with the number format "dddd, mmmm dd, yyyy".
2 - What is the current system date and time. This cell has been formatted with the number format "dddd, mmmm dd, yyyy, hh:mm".