Current week number
Week –
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The year in weeks
Months and week numbers 2026
See how ISO week numbers are distributed across every month. Each week runs from Monday to Sunday.
2026
Wk means week number. Dates shown in a lighter tone belong to the previous or following month.
Keep them close
Week numbers where you need them
Add week numbers to your digital calendar or print a simple template for planning.
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.