ISO week calendar 2027
All 52 ISO weeks of 2027, with the Monday and Sunday that bound each one.
The ISO year 2027 has 52 weeks. Week 1 starts on January 4, 2027 and week 52 ends on January 2, 2028. Every row below is one ISO week, Monday through Sunday.
| ISO week | Monday | Sunday |
|---|---|---|
| Week 1 | January 4, 2027 | January 10, 2027 |
| Week 2 | January 11, 2027 | January 17, 2027 |
| Week 3 | January 18, 2027 | January 24, 2027 |
| Week 4 | January 25, 2027 | January 31, 2027 |
| Week 5 | February 1, 2027 | February 7, 2027 |
| Week 6 | February 8, 2027 | February 14, 2027 |
| Week 7 | February 15, 2027 | February 21, 2027 |
| Week 8 | February 22, 2027 | February 28, 2027 |
| Week 9 | March 1, 2027 | March 7, 2027 |
| Week 10 | March 8, 2027 | March 14, 2027 |
| Week 11 | March 15, 2027 | March 21, 2027 |
| Week 12 | March 22, 2027 | March 28, 2027 |
| Week 13 | March 29, 2027 | April 4, 2027 |
| Week 14 | April 5, 2027 | April 11, 2027 |
| Week 15 | April 12, 2027 | April 18, 2027 |
| Week 16 | April 19, 2027 | April 25, 2027 |
| Week 17 | April 26, 2027 | May 2, 2027 |
| Week 18 | May 3, 2027 | May 9, 2027 |
| Week 19 | May 10, 2027 | May 16, 2027 |
| Week 20 | May 17, 2027 | May 23, 2027 |
| Week 21 | May 24, 2027 | May 30, 2027 |
| Week 22 | May 31, 2027 | June 6, 2027 |
| Week 23 | June 7, 2027 | June 13, 2027 |
| Week 24 | June 14, 2027 | June 20, 2027 |
| Week 25 | June 21, 2027 | June 27, 2027 |
| Week 26 | June 28, 2027 | July 4, 2027 |
| Week 27 | July 5, 2027 | July 11, 2027 |
| Week 28 | July 12, 2027 | July 18, 2027 |
| Week 29 | July 19, 2027 | July 25, 2027 |
| Week 30 | July 26, 2027 | August 1, 2027 |
| Week 31 | August 2, 2027 | August 8, 2027 |
| Week 32 | August 9, 2027 | August 15, 2027 |
| Week 33 | August 16, 2027 | August 22, 2027 |
| Week 34 | August 23, 2027 | August 29, 2027 |
| Week 35 | August 30, 2027 | September 5, 2027 |
| Week 36 | September 6, 2027 | September 12, 2027 |
| Week 37 | September 13, 2027 | September 19, 2027 |
| Week 38 | September 20, 2027 | September 26, 2027 |
| Week 39 | September 27, 2027 | October 3, 2027 |
| Week 40 | October 4, 2027 | October 10, 2027 |
| Week 41 | October 11, 2027 | October 17, 2027 |
| Week 42 | October 18, 2027 | October 24, 2027 |
| Week 43 | October 25, 2027 | October 31, 2027 |
| Week 44 | November 1, 2027 | November 7, 2027 |
| Week 45 | November 8, 2027 | November 14, 2027 |
| Week 46 | November 15, 2027 | November 21, 2027 |
| Week 47 | November 22, 2027 | November 28, 2027 |
| Week 48 | November 29, 2027 | December 5, 2027 |
| Week 49 | December 6, 2027 | December 12, 2027 |
| Week 50 | December 13, 2027 | December 19, 2027 |
| Week 51 | December 20, 2027 | December 26, 2027 |
| Week 52 | December 27, 2027 | January 2, 2028 |
Dates are calendar dates under ISO 8601 week dating. A week belongs to the ISO year that contains its Thursday, which is why the first row can start in late December of the previous calendar year and the last row can end in early January of the next one.
About the 2027 ISO year
After long-year 2026, 2027 returns to the usual 52 weeks. Note the seam between the two years: the first three days of January 2027 are still ISO week 53 of 2026, and ISO 2027 does not begin until Monday, January 4. At the other end, ISO 2027 closes on Sunday, January 2, 2028 — the last two days of the ISO year are calendar days of 2028. Both quirks follow from the same rule: a week belongs to the year of its Thursday.