Weeknumber.io

Current week number

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Week numbers where you need them

Add week numbers to your digital calendar or print a simple template for planning.

Add week numbers to your calendar (.ics) Print calendar templates (PDF)

ISO 8601

How week numbers work

Weeknumber.io follows the international ISO 8601 standard used by businesses and calendars around the world.

  • Weeks start on Monday Monday is day one and Sunday is day seven.
  • The first week has a rule Week 1 is the week containing the year's first Thursday.
  • Most years have 52 weeks Some calendar years contain a week 53.