So! Who remembers the Y2K bug? And the cries
that the end of civilization as we know it is at hand?
Was it all hype? Well, there were indeed serious
fears that older IT equipment might recycle back to 1900 or not
make it through the roll-over into the year 2000, because of the
way they were programmed and dates were represented in that programming.
It was less of a problem for more recent equipment, but this did
not mean that a good, clean transition was guaranteed, and all IT
users everywhere needed to check and verify their systems.
So, all's well that ends well?
Not quite! There is still the little bothersome
business that in order to get from A to B, one can end up with an
airline ticket that says you are travelling from A to C on, for
example, 02-03-02, with a connecting train ticket from C to B carrying
a date of 02-02-03. Has someone invented a time machine?
How can one avoid confusion when a date like
08/04/02 has at least six different interpretations around the world?
A notation like 01/02/03 could mean 1 February 2003 or 2 January
2003 or 2 March 2001. Usually by deduction one can sort it out.
Usually - but sometimes, huge and costly confusions can arise. The
problem is that all-numeric dates are not unambiguous and depend
very much on local custom. That's usually OK within a country or
region even if there are local inconsistencies between firms and
administrations; but outside…?
A simple nicety, you might say. Does this all
matter? Well, it certainly does if you "misinterpreted"
what was on that ticket. And if you multiply this type of unfortunate
occurrence by millions, in business
contexts as well as at the individual level, you can see that the
compounded problem is something quite frightening - well after the
"Y2K bug" scare has receded. Perhaps not in a daily life,
when you write to Cousin Bill in Atlanta, or Auntie Jenny in Australia
where the systems of writing dates may be different. But think of
the number of times that dates and times crop up in business dealings
of all sorts, from insurance forms to travel agencies, from banks
to tax forms. And there, huge stakes hang on dates, that can make
the difference between winning a fortune… or losing it. Goods
being traded internationally are relying on the right dates at each
and every step - and wrong dates often mean wrong deliveries or
no deliveries at all! And dates have caused many problems to computer
On the Internet, all kinds of notations are
used, some language-dependent, and are they all correctly understood
on the other side of the globe? Not so sure. Firms and administrations
make use of dates in most of their daily operations in one form
or another and in most documents used in international trade…
and to have a universally compatible form of representation for
them makes pure good sense.
So then: wouldn't it be wonderful if there
were an internationally agreed standard?
Well, there is.
is ISO 8601, Data elements and interchange
formats – Information interchange – Representation
of dates and times, and we give you here an idea
of how the system functions and the standard works (the full
standard runs to 30 pages). It's a vitally useful tool for businesses
of all kinds, and is totally foolproof. Date representation
may look like a detail, but in reality to avoid those costly
mistakes, isn't it worth investigating a watertight solution?
Data elments and interchange formats– Information interchange
– Representation of dates and times
Price CHF 108.00
ISO members or the
ISO Central Secretariat
ISO 8601:2000 is based on, incorporates and
cancels a variety of previous standards with a view to achieving
one simple, logical and coherent format for all dates, times, and
periods of time requiring to be represented. This system primarily
avoids confusion, but also has the advantage of flexibility; you
can express every element of time or only the ones you need.
The next time you turn up at the airport or
train station on the wrong day, you should demand to know why more
people are not using this standard.
The standard offers representations for the
- Time of the day
- Coordinated universal time (UTC)
- Local time with offset to UTC
- Date and time
- Time intervals
- Recurring time intervals
Representations can be in one of two formats:
a basic format that has a minimal number of characters and an extended
format that adds characters to enhance human readability. For example,
the third of January 2003 can be represented as either 20030103
ISO 8601 advises numeric representation of
dates and times on an internationally agreed basis. It represents
elements from the largest to the smallest element: year-month-day:
date is the most common date representation.
where YYYY is the year in the Gregorian
calendar, MM is the month of the year between 01 (January)
and 12 (December), and DD is the day of the month between
01 and 31.
2003-04-01 represents the first day of April in 2003.
is an alternative date representation used in many commercial
and industrial applications. It is:
where YYYY is the Year in the Gregorian
calendar, ww is the week of the year between 01 (the
first week) and 52 or 53 (the last week), and D is the
day in the week between 1 (Monday) and 7 (Sunday).
2003-W14-2 represents the second day of the fourteenth
week of 2003.
the day is the time representation, using
the 24-hour timekeeping system. It is:
where hh is the number of complete
hours that have passed since midnight, mm is the number
of complete minutes since the start of the hour, and
ss is the number of complete seconds since the start
of the minute.
represents the time one second before midnight.
time represents a specified time of a specified
day. When use is made of the calendar date the representation
where the capital letter T is used
to separate the date and time components. Thus, for
a very precise date and time, look at this:
2003-04-01T13:01:02 represents one minute and two seconds
after one o'clock in the afternoon of 2003-04-01.
The standard has provisions for:
omission of components representing smaller units (seconds,
minutes), where such precision is not needed,
the addition of a decimal fraction to the smallest time unit
where higher precision is needed.
The representations of ISO 8601 offer the following
advantages over many of the locally used representations:
- Easily readable and writeable by systems
- Easily comparable and sortable
- Language independent
- Larger units are written in front
of smaller units
- For most representations the notation
is short and of constant length
Some of the representations permitted by the
standard can be used without further agreement. Others should only
be used by mutual agreement between the communicating partners;
such agreement could be established for instance by mentioning the
representation explicitly in a standard or specification applying
the representation. This will facilitate processing at the receiving
and may be necessary to avoid ambiguity when interpreting ISO 8601
Specifications applying ISO 8601 can have a
need to define the allowed representation of the expressions in
a certain data field. For instance a specification might want to
define that a certain field containing the date and time of an event
should do so in the format: YYYYMMDDhhmm with the exclusion of all
other formats allowed by ISO 8601. In such cases the meta language
used internally in ISO 8601 can be used.
ISO 8601 does not specify the exact meaning
of its representations. This means for example that the standard
does not define whether 09:00 refers to the exact end of the ninth
hour of the day, any other point in the following minute or the
minute as a whole. Users of the standard must agree on a more exact
interpretation of the representation if this is relevant.
ISO 8601 will find usage in computer programmes,
logbooks, contest entries, QSL cards, magazine reports, Web pages,
e-mail, statistics, forms of all kinds, administrations and businesses,
in customs and transportation, in e-commerce and academia, and in
all types of international activity.
ISO 8601 corresponds to the UN Working Party
on the Facilitation of International Trade Procedures in its Recommendation
The new format has already been adopted by
many organizations worldwide. And many more should do so –
to make their own lives simpler. And everybody else's.
Why don't you?
Last modified: 2003-01-30