Week numbers 2026
53 ISO weeksWeek 1: December 29, 2025 – January 4Week 53 ends January 3, 2027
All weeks of 2026
| Week | Monday | Sunday | Month | US week | US federal holiday |
|---|---|---|---|---|---|
| Week 1 | Mon, Dec 29 2025 | Sun, Jan 4 | Dec–Jan | 53/1/2 | New Year's Day |
| Week 2 | Mon, Jan 5 | Sun, Jan 11 | January | 2/3 | |
| Week 3 | Mon, Jan 12 | Sun, Jan 18 | January | 3/4 | |
| Week 4 | Mon, Jan 19 | Sun, Jan 25 | January | 4/5 | Birthday of Martin Luther King, Jr. |
| Week 5 | Mon, Jan 26 | Sun, Feb 1 | Jan–Feb | 5/6 | |
| Week 6 | Mon, Feb 2 | Sun, Feb 8 | February | 6/7 | |
| Week 7 | Mon, Feb 9 | Sun, Feb 15 | February | 7/8 | |
| Week 8 | Mon, Feb 16 | Sun, Feb 22 | February | 8/9 | Washington's Birthday |
| Week 9 | Mon, Feb 23 | Sun, Mar 1 | Feb–Mar | 9/10 | |
| Week 10 | Mon, Mar 2 | Sun, Mar 8 | March | 10/11 | |
| Week 11 | Mon, Mar 9 | Sun, Mar 15 | March | 11/12 | |
| Week 12 | Mon, Mar 16 | Sun, Mar 22 | March | 12/13 | |
| Week 13 | Mon, Mar 23 | Sun, Mar 29 | March | 13/14 | |
| Week 14 | Mon, Mar 30 | Sun, Apr 5 | Mar–Apr | 14/15 | |
| Week 15 | Mon, Apr 6 | Sun, Apr 12 | April | 15/16 | |
| Week 16 | Mon, Apr 13 | Sun, Apr 19 | April | 16/17 | |
| Week 17 | Mon, Apr 20 | Sun, Apr 26 | April | 17/18 | |
| Week 18 | Mon, Apr 27 | Sun, May 3 | Apr–May | 18/19 | |
| Week 19 | Mon, May 4 | Sun, May 10 | May | 19/20 | |
| Week 20 | Mon, May 11 | Sun, May 17 | May | 20/21 | |
| Week 21 | Mon, May 18 | Sun, May 24 | May | 21/22 | |
| Week 22 | Mon, May 25 | Sun, May 31 | May | 22/23 | Memorial Day |
| Week 23 | Mon, Jun 1 | Sun, Jun 7 | June | 23/24 | |
| Week 24 | Mon, Jun 8 | Sun, Jun 14 | June | 24/25 | |
| Week 25 | Mon, Jun 15 | Sun, Jun 21 | June | 25/26 | Juneteenth National Independence Day |
| Week 26 | Mon, Jun 22 | Sun, Jun 28 | June | 26/27 | |
| Week 27 | Mon, Jun 29 | Sun, Jul 5 | Jun–Jul | 27/28 | Independence Day (observed) |
| Week 28 | Mon, Jul 6 | Sun, Jul 12 | July | 28/29 | |
| Week 29 | Mon, Jul 13 | Sun, Jul 19 | July | 29/30 | |
| Week 30 | Mon, Jul 20 | Sun, Jul 26 | July | 30/31 | |
| Week 31 | Mon, Jul 27 | Sun, Aug 2 | Jul–Aug | 31/32 | |
| Week 32 | Mon, Aug 3 | Sun, Aug 9 | August | 32/33 | |
| Week 33 | Mon, Aug 10 | Sun, Aug 16 | August | 33/34 | |
| Week 34 | Mon, Aug 17 | Sun, Aug 23 | August | 34/35 | |
| Week 35 | Mon, Aug 24 | Sun, Aug 30 | August | 35/36 | |
| Week 36 | Mon, Aug 31 | Sun, Sep 6 | Aug–Sep | 36/37 | |
| Week 37 | Mon, Sep 7 | Sun, Sep 13 | September | 37/38 | Labor Day |
| Week 38 | Mon, Sep 14 | Sun, Sep 20 | September | 38/39 | |
| Week 39 | Mon, Sep 21 | Sun, Sep 27 | September | 39/40 | |
| Week 40 | Mon, Sep 28 | Sun, Oct 4 | Sep–Oct | 40/41 | |
| Week 41 | Mon, Oct 5 | Sun, Oct 11 | October | 41/42 | |
| Week 42 | Mon, Oct 12 | Sun, Oct 18 | October | 42/43 | Columbus Day |
| Week 43 | Mon, Oct 19 | Sun, Oct 25 | October | 43/44 | |
| Week 44 | Mon, Oct 26 | Sun, Nov 1 | Oct–Nov | 44/45 | |
| Week 45 | Mon, Nov 2 | Sun, Nov 8 | November | 45/46 | |
| Week 46 | Mon, Nov 9 | Sun, Nov 15 | November | 46/47 | Veterans Day |
| Week 47 | Mon, Nov 16 | Sun, Nov 22 | November | 47/48 | |
| Week 48 | Mon, Nov 23 | Sun, Nov 29 | November | 48/49 | Thanksgiving Day |
| Week 49 | Mon, Nov 30 | Sun, Dec 6 | Nov–Dec | 49/50 | |
| Week 50 | Mon, Dec 7 | Sun, Dec 13 | December | 50/51 | |
| Week 51 | Mon, Dec 14 | Sun, Dec 20 | December | 51/52 | |
| Week 52 | Mon, Dec 21 | Sun, Dec 27 | December | 52/53 | Christmas Day |
| Week 53 | Mon, Dec 28 | Sun, Jan 3 2027 | Dec–Jan | 53/1/2 | New Year's Day |
US week: the Sunday-start number for the same seven days; the ISO week’s Sunday always starts the next US week, and around New Year the US count restarts at 1 on January 1, so a week can carry three numbers (Monday to December 31, January 1 to Saturday, Sunday).
How the weeks of 2026 are numbered
January 1, 2026 is a Thursday, so it falls in week 1, which began on Monday, December 29, 2025. December 31 is in week 53, the last week of the ISO year. 2026 is one of the years with 53 ISO weeks, because January 1, 2026 is a Thursday. Plans built on a 52-week cycle (rotas, payroll, weekly reports) need an extra week this year.
The week number page shows the current week and explains the ISO 8601 rules; the 2026 calendar shows the weeks next to each month.
Which week is it in 2026?
The ISO week of each US federal holiday and of the main observances of 2026, computed from their rules (movable feasts such as Easter and Ramadan included):
- New Year's Day, Thu, Jan 1week 1
- Birthday of Martin Luther King, Jr., Mon, Jan 19week 4
- Valentine’s Day, Sat, Feb 14week 7
- Washington's Birthday, Mon, Feb 16week 8
- Chinese New Year (Fire Horse), Tue, Feb 17week 8
- Ash Wednesday, Wed, Feb 18week 8
- Ramadan begins, Wed, Feb 18week 8
- Mothering Sunday (UK and Ireland), Sun, Mar 15week 11
- Eid al-Fitr, Fri, Mar 20week 12
- Nowruz 1405, Sat, Mar 21week 12
- Palm Sunday, Sun, Mar 29week 13
- Passover (first day), Thu, Apr 2week 14
- Easter Sunday, Sun, Apr 5week 14
- Mother’s Day (US, Canada), Sun, May 10week 19
- Memorial Day, Mon, May 25week 22
- Eid al-Adha, Wed, May 27week 22
- Islamic New Year 1448 AH, Tue, Jun 16week 25
- Juneteenth National Independence Day, Fri, Jun 19week 25
- Father’s Day (US, UK, Canada), Sun, Jun 21week 25
- Independence Day (observed), Fri, Jul 3week 27
- Labor Day, Mon, Sep 7week 37
- Rosh Hashanah 5787, Sat, Sep 12week 37
- Yom Kippur, Mon, Sep 21week 39
- Mid-Autumn Festival, Fri, Sep 25week 39
- Columbus Day, Mon, Oct 12week 42
- Halloween, Sat, Oct 31week 44
- Veterans Day, Wed, Nov 11week 46
- Thanksgiving Day, Thu, Nov 26week 48
- Black Friday (US), Fri, Nov 27week 48
- Hanukkah (first day), Sat, Dec 5week 49
- Christmas Eve, Thu, Dec 24week 52
- Christmas Day, Fri, Dec 25week 52
- New Year’s Eve, Thu, Dec 31week 53
Questions
How many weeks are in 2026?
2026 has 53 ISO weeks, because January 1, 2026 is a Thursday. Week 53 runs from December 28 to January 3, 2027.
When does week 1 of 2026 start?
On Monday, December 29, 2025. January 1, 2026 is a Thursday, so it falls in week 1, which began on Monday, December 29, 2025.
Is there a week 53 in 2026?
Yes: January 1, 2026 is a Thursday, so the ISO year has 53 weeks.
Why do US week numbers differ in 2026?
US-style numbering starts weeks on Sunday and makes the week of January 1 week 1. Because January 1, 2026 is a Thursday, the two systems agree from Monday to Saturday; on Sundays the US number is one higher, because the US week has already started. In the last days of December the US count starts again at 1.