Week Numbers 2027
2027 has 261 working days once Saturdays and Sundays are removed. Week numbers follow ISO 8601, which gives a week to the year that owns its Thursday — that is why 1 January can fall in week 53 of the year before. Marked days: New Year's Day, Martin Luther King Jr. Day, Valentine's Day, Presidents' Day, St Patrick's Day, Easter Sunday. The ones that move are placed by a rule, printed beside each date.
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2027 has 52 ISO weeks. A week belongs to the year that owns its Thursday, which is why some years have 53 and why the first days of January can fall in the last week of the year before.
| Week | Monday | Sunday |
|---|---|---|
| 1 | Mon, January 4, 2027 | Sun, January 10, 2027 |
| 2 | Mon, January 11, 2027 | Sun, January 17, 2027 |
| 3 | Mon, January 18, 2027 | Sun, January 24, 2027 |
| 4 | Mon, January 25, 2027 | Sun, January 31, 2027 |
| 5 | Mon, February 1, 2027 | Sun, February 7, 2027 |
| 6 | Mon, February 8, 2027 | Sun, February 14, 2027 |
| 7 | Mon, February 15, 2027 | Sun, February 21, 2027 |
| 8 | Mon, February 22, 2027 | Sun, February 28, 2027 |
| 9 | Mon, March 1, 2027 | Sun, March 7, 2027 |
| 10 | Mon, March 8, 2027 | Sun, March 14, 2027 |
| 11 | Mon, March 15, 2027 | Sun, March 21, 2027 |
| 12 | Mon, March 22, 2027 | Sun, March 28, 2027 |
| 13 | Mon, March 29, 2027 | Sun, April 4, 2027 |
| 14 | Mon, April 5, 2027 | Sun, April 11, 2027 |
| 15 | Mon, April 12, 2027 | Sun, April 18, 2027 |
| 16 | Mon, April 19, 2027 | Sun, April 25, 2027 |
| 17 | Mon, April 26, 2027 | Sun, May 2, 2027 |
| 18 | Mon, May 3, 2027 | Sun, May 9, 2027 |
| 19 | Mon, May 10, 2027 | Sun, May 16, 2027 |
| 20 | Mon, May 17, 2027 | Sun, May 23, 2027 |
| 21 | Mon, May 24, 2027 | Sun, May 30, 2027 |
| 22 | Mon, May 31, 2027 | Sun, June 6, 2027 |
| 23 | Mon, June 7, 2027 | Sun, June 13, 2027 |
| 24 | Mon, June 14, 2027 | Sun, June 20, 2027 |
| 25 | Mon, June 21, 2027 | Sun, June 27, 2027 |
| 26 | Mon, June 28, 2027 | Sun, July 4, 2027 |
| 27 | Mon, July 5, 2027 | Sun, July 11, 2027 |
| 28 | Mon, July 12, 2027 | Sun, July 18, 2027 |
| 29 | Mon, July 19, 2027 | Sun, July 25, 2027 |
| 30 | Mon, July 26, 2027 | Sun, August 1, 2027 |
| 31 | Mon, August 2, 2027 | Sun, August 8, 2027 |
| 32 | Mon, August 9, 2027 | Sun, August 15, 2027 |
| 33 | Mon, August 16, 2027 | Sun, August 22, 2027 |
| 34 | Mon, August 23, 2027 | Sun, August 29, 2027 |
| 35 | Mon, August 30, 2027 | Sun, September 5, 2027 |
| 36 | Mon, September 6, 2027 | Sun, September 12, 2027 |
| 37 | Mon, September 13, 2027 | Sun, September 19, 2027 |
| 38 | Mon, September 20, 2027 | Sun, September 26, 2027 |
| 39 | Mon, September 27, 2027 | Sun, October 3, 2027 |
| 40 | Mon, October 4, 2027 | Sun, October 10, 2027 |
| 41 | Mon, October 11, 2027 | Sun, October 17, 2027 |
| 42 | Mon, October 18, 2027 | Sun, October 24, 2027 |
| 43 | Mon, October 25, 2027 | Sun, October 31, 2027 |
| 44 | Mon, November 1, 2027 | Sun, November 7, 2027 |
| 45 | Mon, November 8, 2027 | Sun, November 14, 2027 |
| 46 | Mon, November 15, 2027 | Sun, November 21, 2027 |
| 47 | Mon, November 22, 2027 | Sun, November 28, 2027 |
| 48 | Mon, November 29, 2027 | Sun, December 5, 2027 |
| 49 | Mon, December 6, 2027 | Sun, December 12, 2027 |
| 50 | Mon, December 13, 2027 | Sun, December 19, 2027 |
| 51 | Mon, December 20, 2027 | Sun, December 26, 2027 |
| 52 | Mon, December 27, 2027 | Sun, January 2, 2028 |
Which day does the week start on?
US calendars start the week on Sunday and ISO 8601 weeks run Monday to Sunday, so a grid cannot honour both without saying which it is doing. This one is laid out Monday first, as ISO weeks are, and the number down the left is always the ISO week. Layout and numbering agree, which is why this is the version to use when the week number is what matters.
What do the week numbers mean?
These are ISO 8601 weeks: every week runs Monday to Sunday and belongs to the year that owns its Thursday. It is why 1 January 2027 falls in week 53 of 2026, and why a year has 53 weeks whenever it starts on a Thursday or is a leap year starting on a Wednesday. The US business convention of numbering from 1 January gives different answers, and payroll systems disagree about which one they mean.