The International format is the ISO 8601 standard: yyyy-mm-dd (year, month, day).
Using the yyyy-mm-dd format, the 30th of December 2006 would be written as 2006-12-30. The ISO 8601 standard, yyyy-mm-dd, is used in:
* Austria (although the pre-1996 form “d.m.yyyy” is still often used) * Canada (yyyy-mm-dd) (All 3 main types are used in Canada- in French and in English) * China (yyyy-mm-dd or yyyy年mm月dd日) * Germany (possible, but hardly ever appears in public writings. Most often d.m.yyyy is used) * Hong Kong (same as China) * Hungary (yyyy.mm.dd) * Japan (but often in the form yyyy年mm月dd日, or as yy年mm月dd日 when using Japanese era year) * Korea (YYYY년 MM월 DD일) * Latvia (But often dd.mm.yyyy. is used) * Lithuania (yyyy-mm-dd) * Macau (same as China) * Nepal * Poland * South Africa ("d/m/yy" is a common alternative) * Sweden * Taiwan (same as China except year might be represented using ROC era system)
It is often used in scientific, technical or international communication.
Additional information with regards to this format can be found at http://en.wikipedia.org/wiki/ISO_8601