πŸ“†Calendar Tool

Week Number Calculator

Find the ISO week number for any date β€” and browse all weeks of the year.

Current ISO Week
17
Apr 20, 2026 – Apr 26, 2026
111
Day of Year
254
Days Left in Year
17

Year2026
Week StartsApr 20, 2026
Week EndsApr 26, 2026
Day of Year111

2026

W02Jan 5 – Jan 11
W03Jan 12 – Jan 18
W04Jan 19 – Jan 25
W05Jan 26 – Feb 1
W06Feb 2 – Feb 8
W07Feb 9 – Feb 15
W08Feb 16 – Feb 22
W09Feb 23 – Mar 1
W10Mar 2 – Mar 8
W11Mar 9 – Mar 15
W12Mar 16 – Mar 22
W13Mar 23 – Mar 29
W14Mar 30 – Apr 5
W15Apr 6 – Apr 12
W16Apr 13 – Apr 19
W17Apr 20 – Apr 26← Now
W18Apr 27 – May 3
W19May 4 – May 10
W20May 11 – May 17
W21May 18 – May 24
W22May 25 – May 31
W23Jun 1 – Jun 7
W24Jun 8 – Jun 14
W25Jun 15 – Jun 21
W26Jun 22 – Jun 28
W27Jun 29 – Jul 5
W28Jul 6 – Jul 12
W29Jul 13 – Jul 19
W30Jul 20 – Jul 26
W31Jul 27 – Aug 2
W32Aug 3 – Aug 9
W33Aug 10 – Aug 16
W34Aug 17 – Aug 23
W35Aug 24 – Aug 30
W36Aug 31 – Sep 6
W37Sep 7 – Sep 13
W38Sep 14 – Sep 20
W39Sep 21 – Sep 27
W40Sep 28 – Oct 4
W41Oct 5 – Oct 11
W42Oct 12 – Oct 18
W43Oct 19 – Oct 25
W44Oct 26 – Nov 1
W45Nov 2 – Nov 8
W46Nov 9 – Nov 15
W47Nov 16 – Nov 22
W48Nov 23 – Nov 29
W49Nov 30 – Dec 6
W50Dec 7 – Dec 13
W51Dec 14 – Dec 20
W52Dec 21 – Dec 27
W53Dec 28 – Jan 3

How to Use the Week Number Calculator

  1. 1The current week number is shown automatically when you open the page.
  2. 2Select any date from the date picker to look up its week number.
  3. 3View the ISO week number, quarter, day of year, and full calendar details.
  4. 4The year is also shown β€” useful for dates near the turn of a year.
πŸ’‘ISO week 1 is defined as the week containing the first Thursday of the year, which may fall in late December of the previous year.

Week Number FAQ

What is an ISO week number?

ISO week numbers follow the ISO 8601 standard: weeks start on Monday, and week 1 is the week containing the year's first Thursday.

How many weeks are in a year?

Most years have 52 weeks. Some years have 53 ISO weeks, which happens roughly every 5-6 years.

What week number is it today?

The calculator automatically shows the current week number when you load the page.