ISO 8601

ISO 8601 is an international standard to describe dates and times in the easiest way possible for computers to understand.[2]

Date and time according to ISO 8601 [refresh]
Date2024-11-21
Date and time in UTC2024-11-21T08:35:58+00:00
2024-11-21T08:35:58Z
20241121T083558Z
Week2024-W47
Date with week number2024-W47-4
Date without year--11-21[1]
Ordinal date2024-326

This standard is based on putting the biggest types of numbers first and the smallest types of numbers last. Because years are bigger than months, and months are bigger than days, they are put in the order of YEAR-MONTH-DAY.

A basic ISO date for today looks like 2024-11-21.

The basic ISO time is 08:35.

Another very important principle is that when a computer or human puts ISO 8601 dates into alphabetical order, they are also in chronological order.

People can also use these dates, but it is currently not common for people in any country to write dates using this standard in their day-to-day lives, though many Asian countries follow YEAR-MONTH-DAY order.

References

  1. last in ISO8601:2000, in use by "RFC 6350 - vCard Format Specification". IETF. August 2011. Retrieved 2016-06-29. Truncated representation, as specified in [ISO.8601.2000], Sections 5.2.1.3 d), e), and f), is permitted.
  2. ISO, FAQ: Numeric representation of Dates and Time