Week numbers

Find the week number for any date, with the Monday and Sunday that bound it. The tables cover 2026 and 2027, and the year list reaches 2029.

Counted from Wednesday, November 4, 2026. Updated every night.

Most asked this month

This weekWeek 45Weeks in the year53 weeksWeeks left8 weeksNext week startsNov 9

Week numbers in 2026

2026 has 53 ISO weeks. Week 1 starts on Dec 29, 2025.

WeekStarts MondayEnds Sunday
Week 1Dec 29, 2025Jan 4
Week 2Jan 5Jan 11
Week 3Jan 12Jan 18
Week 4Jan 19Jan 25
Week 5Jan 26Feb 1
Week 6Feb 2Feb 8
Week 7Feb 9Feb 15
Week 8Feb 16Feb 22
Week 9Feb 23Mar 1
Week 10Mar 2Mar 8
Week 11Mar 9Mar 15
Week 12Mar 16Mar 22
Week 13Mar 23Mar 29
Week 14Mar 30Apr 5
Week 15Apr 6Apr 12
Week 16Apr 13Apr 19
Week 17Apr 20Apr 26
Week 18Apr 27May 3
Week 19May 4May 10
Week 20May 11May 17
Week 21May 18May 24
Week 22May 25May 31
Week 23Jun 1Jun 7
Week 24Jun 8Jun 14
Week 25Jun 15Jun 21
Week 26Jun 22Jun 28
Week 27Jun 29Jul 5
Week 28Jul 6Jul 12
Week 29Jul 13Jul 19
Week 30Jul 20Jul 26
Week 31Jul 27Aug 2
Week 32Aug 3Aug 9
Week 33Aug 10Aug 16
Week 34Aug 17Aug 23
Week 35Aug 24Aug 30
Week 36Aug 31Sep 6
Week 37Sep 7Sep 13
Week 38Sep 14Sep 20
Week 39Sep 21Sep 27
Week 40Sep 28Oct 4
Week 41Oct 5Oct 11
Week 42Oct 12Oct 18
Week 43Oct 19Oct 25
Week 44Oct 26Nov 1
Week 45Nov 2Nov 8
Week 46Nov 9Nov 15
Week 47Nov 16Nov 22
Week 48Nov 23Nov 29
Week 49Nov 30Dec 6
Week 50Dec 7Dec 13
Week 51Dec 14Dec 20
Week 52Dec 21Dec 27
Week 53Dec 28Jan 3, 2027

The current week is marked in blue. A week that crosses New Year belongs to the year that holds its Thursday.

Week numbers in 2027

2027 has 52 ISO weeks. Week 1 starts on Jan 4, 2027.

WeekStarts MondayEnds Sunday
Week 1Jan 4Jan 10
Week 2Jan 11Jan 17
Week 3Jan 18Jan 24
Week 4Jan 25Jan 31
Week 5Feb 1Feb 7
Week 6Feb 8Feb 14
Week 7Feb 15Feb 21
Week 8Feb 22Feb 28
Week 9Mar 1Mar 7
Week 10Mar 8Mar 14
Week 11Mar 15Mar 21
Week 12Mar 22Mar 28
Week 13Mar 29Apr 4
Week 14Apr 5Apr 11
Week 15Apr 12Apr 18
Week 16Apr 19Apr 25
Week 17Apr 26May 2
Week 18May 3May 9
Week 19May 10May 16
Week 20May 17May 23
Week 21May 24May 30
Week 22May 31Jun 6
Week 23Jun 7Jun 13
Week 24Jun 14Jun 20
Week 25Jun 21Jun 27
Week 26Jun 28Jul 4
Week 27Jul 5Jul 11
Week 28Jul 12Jul 18
Week 29Jul 19Jul 25
Week 30Jul 26Aug 1
Week 31Aug 2Aug 8
Week 32Aug 9Aug 15
Week 33Aug 16Aug 22
Week 34Aug 23Aug 29
Week 35Aug 30Sep 5
Week 36Sep 6Sep 12
Week 37Sep 13Sep 19
Week 38Sep 20Sep 26
Week 39Sep 27Oct 3
Week 40Oct 4Oct 10
Week 41Oct 11Oct 17
Week 42Oct 18Oct 24
Week 43Oct 25Oct 31
Week 44Nov 1Nov 7
Week 45Nov 8Nov 14
Week 46Nov 15Nov 21
Week 47Nov 22Nov 28
Week 48Nov 29Dec 5
Week 49Dec 6Dec 12
Week 50Dec 13Dec 19
Week 51Dec 20Dec 26
Week 52Dec 27Jan 2, 2028

The current week is marked in blue. A week that crosses New Year belongs to the year that holds its Thursday.

Weeks in each year

Most years have 52 ISO weeks. A year with a Thursday on January 1, or a leap year that starts on a Wednesday, has 53.

YearWeek 1 startsWeeksWeekday of January 1
2025Dec 30, 202452Wednesday
2026Dec 29, 202553Thursday
2027Jan 4, 202752Friday
2028Jan 3, 202852Saturday
2029Jan 1, 202952Monday

Week 1 can begin in late December of the year before.

Work with a week

Move a date by a number of weeks, or count the days between two dates.

Weeks until

Dates and calendars

How ISO week numbers work

The ISO 8601 standard numbers weeks so that every week runs Monday to Sunday. Week 1 is the week that holds the first Thursday of the year.

That rule means January 4 is always in week 1. It also means the first days of January can sit in the last week of the year before.

The same rule explains why late December can fall in week 1 of the next year. The week belongs to the year that owns most of its days.

Why a year has 52 or 53 weeks

A normal year is 52 weeks and one day, and a leap year is 52 weeks and two days. The extra days build up until a 53rd week is needed.

About one year in five or six has 53 weeks. The tables above name the next few, so you can plan around them.

A 53 week year matters for payroll, school terms and budgets that run by the week. One more week can mean an extra pay period.

US and other week systems

The United States often starts the week on Sunday and counts week 1 as the week that holds January 1. That can differ from the ISO number by one.

The UK, Canada and Australia use Monday as the first day in business calendars. ISO numbers are common in planning and shipping.

Check which system a form or a calendar app uses before you rely on a week number. The dates in our tables are always the ISO ones.

Questions people ask

What week of the year is it?

Today is week 45 of 2026, counted by the ISO 8601 rule. The week runs Monday to Sunday.

How many weeks are in 2026?

2026 has 53 ISO weeks. Week 1 starts on Dec 29, 2025.

Which week is the first week of the year?

Week 1 is the week with the first Thursday of the year. January 4 is always in it.

Does the week start on Sunday or Monday?

ISO weeks start on Monday. Some US calendars start on Sunday, so check the system your form uses.

Can a year have 53 weeks?

Yes. About one year in five or six has 53 ISO weeks. The table of years above shows which ones.

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