The first Thursday decides
Week 1 is the week with the year's first Thursday, so January 1 can sit in the last week of the year before.
What week is it?
Today's week number by ISO 8601, and every week of 2026 with its dates. Weeks start on Monday.
This week
Week 45
Mon, Nov 2, 2026 to Sun, Nov 8, 2026
Today is Wed, Nov 4, 2026, day 308 of the year. ISO week 45 of 2026.
Week 18 weeks left in 2026
November 2026
WkMTWTFSS
442627282930311
452345678
469101112131415
4716171819202122
4823242526272829
4930123456
Week numbers of 2026
53 weeks, each from Monday to Sunday. This week is filled in.
Week 1
Dec 29 to Jan 4
Week 2
Jan 5 to Jan 11
Week 3
Jan 12 to Jan 18
Week 4
Jan 19 to Jan 25
Week 5
Jan 26 to Feb 1
Week 6
Feb 2 to Feb 8
Week 7
Feb 9 to Feb 15
Week 8
Feb 16 to Feb 22
Week 9
Feb 23 to Mar 1
Week 10
Mar 2 to Mar 8
Week 11
Mar 9 to Mar 15
Week 12
Mar 16 to Mar 22
Week 13
Mar 23 to Mar 29
Week 14
Mar 30 to Apr 5
Week 15
Apr 6 to Apr 12
Week 16
Apr 13 to Apr 19
Week 17
Apr 20 to Apr 26
Week 18
Apr 27 to May 3
Week 19
May 4 to May 10
Week 20
May 11 to May 17
Week 21
May 18 to May 24
Week 22
May 25 to May 31
Week 23
Jun 1 to Jun 7
Week 24
Jun 8 to Jun 14
Week 25
Jun 15 to Jun 21
Week 26
Jun 22 to Jun 28
Week 27
Jun 29 to Jul 5
Week 28
Jul 6 to Jul 12
Week 29
Jul 13 to Jul 19
Week 30
Jul 20 to Jul 26
Week 31
Jul 27 to Aug 2
Week 32
Aug 3 to Aug 9
Week 33
Aug 10 to Aug 16
Week 34
Aug 17 to Aug 23
Week 35
Aug 24 to Aug 30
Week 36
Aug 31 to Sep 6
Week 37
Sep 7 to Sep 13
Week 38
Sep 14 to Sep 20
Week 39
Sep 21 to Sep 27
Week 40
Sep 28 to Oct 4
Week 41
Oct 5 to Oct 11
Week 42
Oct 12 to Oct 18
Week 43
Oct 19 to Oct 25
Week 44
Oct 26 to Nov 1
Week 45this week
Nov 2 to Nov 8
Week 46
Nov 9 to Nov 15
Week 47
Nov 16 to Nov 22
Week 48
Nov 23 to Nov 29
Week 49
Nov 30 to Dec 6
Week 50
Dec 7 to Dec 13
Week 51
Dec 14 to Dec 20
Week 52
Dec 21 to Dec 27
Week 53
Dec 28 to Jan 3
How week numbers work
52 or 53 weeks
A year has 53 ISO weeks when January 1 is a Thursday, or a Wednesday in a leap year. 2026 has 53.
Why your calendar may differ
Some calendars, notably in the US, start weeks on Sunday and count the week with January 1 as week 1. That can differ from the ISO number by one.
Other years
More free tools
Frequently asked questions
Fai una domandaBy ISO 8601, the standard most calendars and businesses use: a week runs from Monday to Sunday, and week 1 is the week that holds the year's first Thursday (so January 1 can be in week 52 or 53 of the year before, and December 29 to 31 can be in week 1 of the next). A year has 52 or 53 weeks.
53. A year has 53 ISO weeks when January 1 is a Thursday, or a Wednesday in a leap year.
Some calendars, notably in the US, start weeks on Sunday and count the week with January 1 as week 1. That system can differ from the ISO number by one. Check your calendar's settings: most offer ISO weeks.