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📆Week Number Calculator

Find the ISO week number for any date and see the full week calendar.

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ISO Week Number

W14

of 2026Saturday

94

Day of Year

Q2

Quarter

38

Weeks Remaining

About Week Number Calculator

Find the ISO 8601 week number for any date and see the full calendar week it belongs to, including start and end dates. Useful for project scheduling, payroll periods, and any business process that references weeks by number.

How to Use Week Number Calculator

  1. 1

    Enter a date

    Select or type the date you want to look up.

  2. 2

    View the week number

    See the ISO week number and the full Monday-to-Sunday range for that week.

  3. 3

    Navigate weeks

    Step forward or backward through weeks to explore the calendar.

Common Use Cases

  • Identifying week numbers for project planning and scheduling
  • Calculating payroll or billing periods by week number
  • Coordinating international business schedules that use ISO weeks
  • Reporting and analytics that aggregate data by week

Frequently Asked Questions

What is ISO week numbering?
ISO 8601 defines week 1 as the week containing the year's first Thursday. Weeks run Monday to Sunday, and a year can have 52 or 53 weeks.
Can I look up which dates fall in a given week number?
Yes, you can enter a year and week number to find the exact Monday-to-Sunday date range for that week.

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