Weekmark

Calendar week · ISO 8601

Week 1, 2027

Monday 4 January – Sunday 10 January 2027

  1. Mon4Jan
  2. Tue5Jan
  3. Wed6Jan
  4. Thu7Jan
  5. Fri8Jan
  6. Sat9Jan
  7. Sun10Jan
ISO week
2027-W01
Copy as
CW1 (4–10 Jan)
Quarter
Q1 2027
Weeks in 2027
52
US week number
2

Week 1 is also written KW 1 (Kalenderwoche) or CW 1. ISO weeks start on Monday, and week 1 is the week with the year’s first Thursday. US calendars start weeks on Sunday and count the week with 1 January as week 1, so they give Monday 4 Jan to Saturday 9 Jan a different number: week 2.