ISOWEEKNUM

Returns the number of the ISO (International Organization for Standardization) week of the year where the provided date falls.

Sample Usage

ISOWEEKNUM(DATE(1969, 7, 20))

ISOWEEKNUM("6/14/2002")

Syntax

ISOWEEKNUM(date)

  • date - The date for which to determine the ISO week number. Must refer to a cell containing a date, number, or function returning a date type.

Notes

  • When entering the date, use the DATE function, as text values might return errors.
  • Per the European system for numbering weeks (also known as ISO 8601):
    • Weeks begin on Monday and end on Sunday.
    • Week 1 of the year is the week containing the first Thursday of the year.
      • As a result, if the first Thursday is after January 4, at least one of the following days, January 1-3, will have an ISOWEEKNUM of 52 or 53.
      • Similarly, if the first Thursday is before January 4, at least one of the following days, December 29-31, will have an ISOWEEKNUM of 1. 
      • If the first Thursday is January 4, December 29-31 of the previous year will have ISOWEEKNUM of 52 and January 1-7 of the current year will have ISOWEEKNUM of 1.

See Also

  • WEEKNUM: Returns a number representing the week of the year where the provided date falls.
  • WEEKDAY: Returns a number representing the day of the week of the date provided.
  • DAYS360: Returns the difference between two days based on the 360-day year used in some financial interest calculations.
  • DATE: Converts a year, month, and day into a date.
  • DATEVALUE: Converts a provided date string in a known format to a date value.
true
Visit the Learning Center

Using Google products, like Google Docs, at work or school? Try powerful tips, tutorials, and templates. Learn to work on Office files without installing Office, create dynamic project plans and team calendars, auto-organize your inbox, and more.

Search
Clear search
Close search
Google apps
Main menu
6007518427652579358
true
Search Help Center
true
true
true
true
true
35
false
false