It is currently week 43 of 53 in 2026 (today is Wednesday, October 21, 2026). The week runs from Monday, October 19, 2026 to Sunday, October 25, 2026.
This page uses ISO 8601 week numbers: weeks start on Monday, and week 1 is the week containing the year's first Thursday (equivalently, the week of January 4). Under this system a year has 52 or 53 weeks — 2026 has 53.
=ISOWEEKNUM(TODAY()) returns the ISO week number (the one shown here). =WEEKNUM(TODAY()) uses the US convention, where week 1 starts on January 1 and weeks start on Sunday, so it can differ by one. Both work in Excel and Google Sheets.
2026 has 53 ISO weeks. Most years have 52; a year has 53 when it starts on a Thursday (or on a Wednesday in a leap year).