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Campaign to get the Internet World to use the
International Date Format
ISO 8601
Ever been to a webpage to see that the time-sensitive information you
are interested in is dated 03/05/01?
Is this date the 3rd of May 2001 or the 5th of March 2001 or
the 1st of May 2003 and does the 01 refer to 2001
in the first two cases?
In order to make the right choice, you must ask yourself some questions :
- Where is the website you are visiting based?
- Is the website in a country which supports the U.S.A. style date format (mm/dd/yy) or
the European style (dd/mm/yy)?
- Which countries do officially use the U.S.A. style date format? Is there an
official list?
- Is the page author :
- American?
- European?
- Japanese?
- someone who thinks or wishes he/she was one of these nationalities?
- one of these nationalities living in a foreign country?
- someone using a particular format because they think it is a world standard?
- confused, and has got the numeric fields in an order different to what they intended?
Which one is it? It could
be very important to you.
The Internet is a truly International method of communicating - there are no political
or cultural boundaries drawn on the www page you call up - the page could have been stored
in the Smithsonian Institute or on a small server in a basement in Ulan Bator, Mongolia.
Often, you have no way of telling. So, if anyone in the world can read your page, why not
ensure that any date references on that page can be read correctly and unambiguously by
that person, by using the ISO 8601:1988 International Date Format.
So what is this date format?
CCYY-MM-DD
where CC is the century
(representing the digits used in the thousands and hundreds components, as opposed to the
actual century), YY is the year, MM
is the month of the year between 01 (January) and 12 (December), and DD
is the day of the month between 01 and 28 or 29 or 30 or 31, depending on length of month
and whether it is a leap year. These dates are using the Gregorian calendar.
For example : 2001-01-15 is the fifteenth of January in the year two
thousand and one A.D. - completely unambiguous
Simple, isn't it?
Eleven good reasons to use it
- language independent - a true international standard from the International Organisation for
Standardisation (see Note 1 below)
- cannot be confused with any other popular date notations
- consistency with the common time notation system, where the larger unit (hour) is
written in front of the smaller ones (minutes and seconds)
- easily readable and writeable by software (no month name to number conversion
necessary)
- easily comparable and sortable with a trivial string comparison
- strings containing a date followed by a time are also easily comparable and sortable
e.g. 1996-01-15 22:45:37 with most significant value to the left
- the notation is short and has constant length, which makes both keyboard data
entry and table layout easier
- identical to the Chinese date notation, so the largest cultural group (>25%)
on this planet is already familiar with it - so no feeble excuses like "but no-one
uses this format..."
- date notations with the order "year, month, day" are in already widely used
in Japan, Korea, Hungary, Sweden, Finland, Denmark to name just a few. Even people in the US
are already used to at least the "month, day" ordering
- a 4-digit year representation would have avoided the Year 2000 problem. If only
they had thought of that when computer technology was being developed...
- Astronomers have been using this format for centuries
Note 1 : there are several calendars in use around the world using different reference
points (eg. AD 1996 in the Jewish calendar is 5757, in the Islamic calendar 1417) but
whenever any of the people using a local calendar speak to anyone outside their calendar
regime, they use the Gregorian calendar, so this can be considered to be the international
standard for date representation.
A bucket full of stuff on calendars is available
elsewhere
The International Date
Format is designed for the time-stamping of data, events and information so
that anyone in the world, of any nationality will know, without ambiguity, which date this
identifier relates to. For example : press releases, scientific papers, sell-by/use-by
dates, legal documents, any time-stamped data, important events in the future or past.
Do you wish to download your own copy of the full
ISO8601 standard?
Unfortunately, you cannot download your own copy of the latest version
of the standard unless you pay some money to ISO.
Seems pretty daft to me - if you want a worldwide standard to be adopted it should be
freely available to everyone who could possibly want to use it.... maybe the Internet will
change this.
Older versions are available and you can download them from the ISO8601 group files section.
Page last updated 2001-02-22
 
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