Return the week number of the current date

	A	B
1	=TODAY() = Monday, February 03, 2025
2	=NOW() = Monday, February 03, 2025
3	=ISOWEEKNUM((A1)) = 6
4	=TRUNC(((A1-DATE(YEAR(A1), 1, 0))+6)/7) = 5
5	=INT((A1-DATE(YEAR(?-4337), 1, 1))/7)+1 = 6528

Built-in Functions

TODAY - The date serial number representing today's date.
NOW - The date serial number of the current system date and time.
ISOWEEKNUM - The number of the ISO week of the year for a given date.