Calendar week · ISO 8601
Week 40, 2027
Monday 4 October – Sunday 10 October 2027
- Mon4Oct
- Tue5Oct
- Wed6Oct
- Thu7Oct
- Fri8Oct
- Sat9Oct
- Sun10Oct
- ISO week
2027-W40- Copy as
CW40 (4–10 Oct)- Quarter
- Q4 2027
- Weeks in 2027
- 52
- US week number
- 41
Week 40 is also written KW 40 (Kalenderwoche) or CW 40. 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 Oct to Saturday 9 Oct a different number: week 41.