Week Number Calculator
What week is it? Dates of a weekRuns locally · nothing uploaded
Also works as:what week is itISO week numberweek number to date
How to use
- 1Choose date → week or week → dates.
- 2Enter a date, or a year and week.
- 3Read the result.
FAQ
How are ISO week numbers defined?
Weeks start on Monday and week 1 is the week containing January 4 (the year's first Thursday). Years have 52 or 53 weeks.
Why can late December be week 1?
Under ISO rules a week belongs to the year that contains its Thursday.