Week Number Calculator

Find the ISO-8601 week number and year progress for any given date.

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This tool uses the ISO-8601 standard, where Week 1 is the first week with at least 4 days in the new year.

Week Number

CURRENT WEEK

Week RangeFeb 02 - Feb 08, 2026

Weeks in 202653

Year Progress8.8%

ISO-8601 Standard

The ISO week-numbering system is part of the ISO 8601 date and time standard. It is used mostly in government and business for fiscal years, as well as in timekeeping. The system uses 52 or 53 full weeks (364 or 371 days) per year. Week 1 always contains the 4th of January.