Use International Date Formats

Internationalization of software is always difficult. The linguistic and cultural differences around the globe adds to the problem. I think that the the simplest thing to sort out is the date representation. As with any other different countries denote dates differently.

Karl Dubost says it best in the W3C website:

The worst potential usability problems come when the date is written only with numbers as in the following example, because the date’s interpretation will be different from one country to another.

Imagine the following date: 02/04/03

Which does it mean?

1. 2nd of April 2003 (European style)
2. 4th of February 2003 (USA style)
3. 3rd of April 2002

Your answer will depend, mostly, on which country you live in.

To address these problems, the ISO defined a new international date format (ISO 8601). In this standard, the dates are formatted as: YYYY-MM-DD

For example, “3rd of April 2002″ becomes 2002-04-03 in this international format. This format also supports precise date and time, with timezone information.

The main advantage of this scheme is that it causes the least confusion. If we were to denote a date as 02/04/03, there would be confusion about whether the date is in the format DD-MM-YYYY or MM-DD-YYYY. Since the ISO standard starts with YYYY, it is pretty obvious that MM-DD follows. (Nobody uses the YYYY-DD-MM format. See the wikipedia entry)

Another major feature is that when dates in this format are ordered sequentially by the leading number, this also orders them in date order. So a simple sort of th string produces the dates also in sorted order. This was not possible using the MM-DD-YYYY or DD-MM-YYYY formats. Sorting dates needed a thinking programmer then.

Other advantages according to the ISO specification are:

• Easily readable and writeable by systems
• Easily comparable
• Language independent
• Larger units are written in front of smaller units
• For most representations the notation is short and of constant length

So use the ISO date format in your programs and web apps. It greatly enhances the usability of your applications and helps in addressing the needs of a more global community.