Week Number Calculator
What ISO week of the year
Week Number
Type 8 digits (e.g. 20000101 → 2000-01-01), or use the 📅 calendar.
This year
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※ ISO 8601 week number (weeks start Monday; week 1 contains the year first Thursday).
Details
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FAQ
What week is it?
Enter a date for the ISO 8601 week number. ISO weeks start on Monday and week 1 is the week containing the year first Thursday.
Different from my calendar?
Possibly. Some systems use the week containing Jan 1 as week 1, or start weeks on Sunday.
Day of year too?
Yes, it also shows how many days into the year the date is.
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