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by Nick Renton

This essay discusses the date formats used on this site.

Every cheque, every invoice, every receipt and every entry in an accounting ledger bears a date. But few people give much thought as to the best way to write dates.

Computer users in general and Internet surfers in particular will be familiar with a very annoying American habit.

The United States practice is to express dates in the quite illogical month-day-year (MMDDYY) format. To show the month, which comes between the day and the year in order of magnitude, in this way is clearly absurd. Australia and the rest of the world mostly use day-month-year (DDMMYY).

While better quality software often gives non-US users the choice of using a local date format web pages and many programs do not. Their authors adopt the typical American way of looking at everything parochially, not even recognising the ambiguity which their approach creates. Does 03/04/02 mean 3 April 2002 or 4 March 2002 (or perhaps even 2 April 2003)?

However, there is a convenient way around this. The International Organization for Standardization (ISO) has laid down a standard, ISO 8601, which prescribes a new way for setting out dates. This is YYYY-MM-DD (for example, 2002-03-04) and it could be regarded as a metric date format suitable for use universally.

The year is expressed using four digits, thus avoiding another possible ambiguity familiar to readers of millennium bug stories: does 02 mean 1902 or 2002?

The separator is standardised as a hyphen rather than as either a slash or a full stop - this change in itself serving as a subtle reminder that a modern date format is being used. Of course, the two hyphens can be omitted in contexts where saving space is more important than readability.

Two digits are always used for months and days (values less than 10 thus involve an initial 0). Furthermore, months are always shown in a straightforward digital form, avoiding the style inconsistencies between 5 August, 5th August, August 5, 05 Aug, the European 5 VIII and many more.

This way of rendering dates would complement the use of metric weights and measures and metric paper sizes (A4, etc.). It would fit in with the two main principles of the metric system - simplicity and uniformity throughout the civilised world.

Year-month-day is clearly logical in that it follows the philosophy of our normal system of expressing numbers. Units are arranged from the largest at the left to the smallest at the right - for example, thousands, hundreds, tens and ones. Time is often expressed in a similar fashion as hours-minutes-seconds.

The ISO is a non-government body and its standards are market-driven and based on consensus. Adoption of the new standard would not prevent the subsequent introduction of other much needed calendar reforms such as the World Calendar (four equally sized quarters each year) or a uniform date for Easter.

The advantages of a metric date format would include the following:

  • The sorting of items into date order would be facilitated.
  • The ambiguity between practices in the United States and the rest of the world would be eliminated.
  • The system copes readily cope with dates in both the 20th and 21st centuries.
  • The uniform length would aid tabular presentations.
  • Numbers, dates and time would all be treated consistently.
  • The "month-day" part of the dates would fit in with the current US practice.

Japan already uses ISO 8601.

It would clearly be preferable for Australia to follow suit and adopt ISO 8601 on a national basis and to do so with the enthusiastic involvement of both the State and Federal Governments as well as the private sector.

However, there is nothing to stop Australians from adopting it even now for any written or printed material which they create.

The use of the International Date Format is particularly desirable for material likely to be seen in other countries, including web pages.

The International Date Format deserves the active support of the business community, the computer industry and the media.

©2002 N E Renton. All rights reserved.

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The Open Directory Project (ODP) has many links to sites discussing the ISO 8601 Standard.

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This page http://nickrenton.com/301.htm was last updated on 2006-10-02