Syntax

ISOWEEKNUM(date)

Arguments

The printed syntax lists 1 argument(s), in order:

  • date

“optional” marks an argument Google prints in square brackets; “repeatable” marks one Google prints with “…”.

Description from Google Docs Editors Help

“Returns the number of the ISO week of the year where the provided date falls.”

Google’s help article for ISOWEEKNUM →

Source: Google Docs Editors Help, “Google Sheets function list” (support.google.com/docs/table/25273), record record 11 of 516, data fetched 28 September 2026. Data month: September 2026.