Week Number Calculator
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Formula: ISO 8601: Week 1 contains January 4th
ISO 8601: Week 1 contains January 4th
Step-by-Step Examples
January 1, 2024 = Week 1
Jan 1 falls in week 1 of 2024
Frequently Asked Questions
What is the current week number?
Enter today's date to find out. Most years have 52 weeks; some have 53.
Do all years have 52 weeks?
Most years have 52 ISO weeks. Years starting on Thursday (or leap years starting on Wednesday) have 53 weeks.
What day does an ISO week start on?
Monday. The ISO 8601 standard defines Monday as the first day of the week.