How it works
Week Number Calculator is designed to give you the result immediately. The calculation or processing happens on your device for this tool, so normal use does not require an account or a file upload.
Privacy
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Find ISO 8601 week numbers
Calculate the ISO week and ISO week-numbering year for any date. ISO weeks start on Monday, and week 1 is the week containing the year's first Thursday.
- ISO 8601 week
- Monday-based weeks
- Week-numbering year
- Useful for reporting and sprint planning