Computer & Digital
ISO 8601 Week Date
International standard · week-numbered
The international standard for unambiguous dates, including week numbering: weeks start on Monday, and week 1 is the one holding the year’s first Thursday.
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In UTC at 02:02 on October 27, 2026, this calendar read 2026-W44-2. The reading above is live, in your own time zone.
At a glance
- Type
- Solar — the Gregorian year, numbered by week
- Origin
- The ISO 8601 standard, first published in 1988
- Year
- 52 or 53 weeks
- Week
- 7 days, starting Monday; week 1 holds the year’s first Thursday
- Leap rule
- A 53rd week when 1 January is a Thursday, or a Wednesday in a leap year
- Counts from
- The Gregorian era
- Where it’s used
- Business, government and software worldwide — especially in Europe
- How it’s worked out here
- Exact arithmetic from the date in your time zone
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