Week numbers 2026
2026 has 53 weeks. Week 1 runs from Monday, December 29, 2025 to Sunday, January 4, 2026, and week 53 ends on Sunday, January 3, 2027. The dates below follow ISO 8601: weeks start on Monday, and week 1 is the week with the year's first Thursday.
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Dates of a week
Week numbers 2026
ISO 8601 weeks start on Monday, and week 1 is the week with the year's first Thursday.
| Week | Monday | Sunday |
|---|---|---|
| 1 | Dec 29, 2025 | Jan 4 |
| 2 | Jan 5 | Jan 11 |
| 3 | Jan 12 | Jan 18 |
| 4 | Jan 19 | Jan 25 |
| 5 | Jan 26 | Feb 1 |
| 6 | Feb 2 | Feb 8 |
| 7 | Feb 9 | Feb 15 |
| 8 | Feb 16 | Feb 22 |
| 9 | Feb 23 | Mar 1 |
| 10 | Mar 2 | Mar 8 |
| 11 | Mar 9 | Mar 15 |
| 12 | Mar 16 | Mar 22 |
| 13 | Mar 23 | Mar 29 |
| 14 | Mar 30 | Apr 5 |
| 15 | Apr 6 | Apr 12 |
| 16 | Apr 13 | Apr 19 |
| 17 | Apr 20 | Apr 26 |
| 18 | Apr 27 | May 3 |
| 19 | May 4 | May 10 |
| 20 | May 11 | May 17 |
| 21 | May 18 | May 24 |
| 22 | May 25 | May 31 |
| 23 | Jun 1 | Jun 7 |
| 24 | Jun 8 | Jun 14 |
| 25 | Jun 15 | Jun 21 |
| 26 | Jun 22 | Jun 28 |
| 27 | Jun 29 | Jul 5 |
| Week | Monday | Sunday |
|---|---|---|
| 28 | Jul 6 | Jul 12 |
| 29 | Jul 13 | Jul 19 |
| 30 | Jul 20 | Jul 26 |
| 31 | Jul 27 | Aug 2 |
| 32 | Aug 3 | Aug 9 |
| 33 | Aug 10 | Aug 16 |
| 34 | Aug 17 | Aug 23 |
| 35 | Aug 24 | Aug 30 |
| 36 | Aug 31 | Sep 6 |
| 37 | Sep 7 | Sep 13 |
| 38 | Sep 14 | Sep 20 |
| 39 | Sep 21 | Sep 27 |
| 40 | Sep 28 | Oct 4 |
| 41 | Oct 5 | Oct 11 |
| 42 | Oct 12 | Oct 18 |
| 43this week | Oct 19 | Oct 25 |
| 44 | Oct 26 | Nov 1 |
| 45 | Nov 2 | Nov 8 |
| 46 | Nov 9 | Nov 15 |
| 47 | Nov 16 | Nov 22 |
| 48 | Nov 23 | Nov 29 |
| 49 | Nov 30 | Dec 6 |
| 50 | Dec 7 | Dec 13 |
| 51 | Dec 14 | Dec 20 |
| 52 | Dec 21 | Dec 27 |
| 53 | Dec 28 | Jan 3, 2027 |
Week numbers in your calendar
Each Monday gets an all day event with its week number, from last year to three years ahead. Subscribe once and it stays up to date.
For scripts and AI agents, every week of 2026 is also plain JSON: 2026.json.
Need the days or working days between two dates? Use the day counter.
Plan your team's weeks
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Questions
- How are week numbers counted?
With ISO 8601, the standard Europe and most of the world use. Weeks start on Monday, and week 1 is the week with the year's first Thursday, which is also the week with January 4. So the last days of December can be in week 1 of the next year, and the first days of January in week 52 or 53 of the year before.
- How many weeks are in 2026?
2026 has 53 ISO weeks. A year has 53 weeks when it starts on a Thursday, or on a Wednesday in a leap year. 2026 and 2032 have 53, 2027 and 2028 have 52.
- When does week 1 of 2026 start?
On Monday, December 29, 2025. It ends on Sunday, January 4, 2026.
- Why is my US colleague's week number different?
In the US, weeks usually start on Sunday and week 1 is the week of January 1, whatever day that is. Both systems often agree, but not always: in years like 2027, where January 1 is a Friday, the US week number is one higher than the ISO one for most of the year. Pick US (Sunday) at the top of this page to see the US numbers.
- How do I show week numbers in Google Calendar?
On the web, click the gear icon, then Settings > General > View options, and check Show week numbers. To see the number as an event on your phone too, subscribe to the week numbers calendar under Week numbers in your calendar on this page.
- How do I show week numbers in Outlook?
In the new Outlook and Outlook on the web, open the calendar, then View > Calendar settings > Calendar appearance, check Show week numbers and save. For ISO numbers, set Start the first week of the year on to the first four-day week. In classic Outlook, go to File > Options > Calendar and check Show week numbers in the month view and in the Date Navigator.
- How do I get the week number of a date in Excel or Google Sheets?
Use
=ISOWEEKNUM(A1)for the ISO week number of the date in A1.=WEEKNUM(A1)gives the US week number, with weeks starting on Sunday.
Reminders in Slack
TurnShift is this calendar for teams on Slack: each person gets a message before their shift, and books their own shifts from there.