National Physical Laboratory

Is there an approved way to represent dates and times? (FAQ - Time)

Both the British Standards Institute (BSI) and the International Organization for Standardization (ISO) publications describe a common format for the standard representation of date, time of day, and combinations of dates. For example, the standard notation for the date is the sequence YYYY-MM-DD or YY-MM-DD.

The relevant standards are:

  • BS EN 28601 : 1992
    ’Specification for representation of dates and times in information interchange'
    (NB. BS EN 28601 replaced BS 7151 : 1989)
  • ISO 8601 : 2004
    'Data elements and interchange formats - information interchange - Representation of dates and times'
Last Updated: 25 Mar 2010
Created: 9 Aug 2007


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