ISO 8601

Here in this modern world, things should be simple and unambiguous. If only this were true! Here's a simple example:

01/02/03

I now tell you that this is a date. When is it?

• 1st February, 2003?
• 2nd January, 2003?
• 3rd February, 2001?

All these are in use in various parts of our world, and can make life on the internet confusing, at the least. The "MM/DD/YY" format is common in U.S.A., here in Australia and in the UK the format "DD/MM/YY" is widely used. And in Europe and parts of Asia, "YY/MM/DD" is in common use. So what can be done? Simple, follow the standard: ISO 8601:1988 - International Date Format. For dates, this standard recommends the following format:

YYYY-MM-DD

This format has a few advantages:

1. It is unambiguous. A useful trait, one would think.
2. It has a consistent length.
3. It may be easily sorted (for those UNIX geeks, think sort(1)).
4. It is recognised by far more people world wide than any other format.
5. It is consistent with common time formats (HH:MM:SS), that is, most significant units come first.
6. It is a standard, from the International Organisation for Standardisation.

Please, can we start using this?

See Also

• ISO 8601 at www.wikipedia.org.
• Obligatory xkcd on ISO 8601, and the Explain xkcd page.
• Date format by country at www.wikipedia.org.
• Date and time notation by country at www.wikipedia.org.
• Calendar date at www.wikipedia.org.
• RFC 3339 vs ISO 8601 includes a large set of examples.
• A Summary of the International Standard Date and Time Notation by Markus Kuhn.
• RFC 3339: Date and Time on the Internet: Timestamps.
• W3C Date and Time Formats.
• UTC is enough for everyone, right?.