Date and time notation in Australia

Date

The written date format in Australia, as in the UK and New Zealand, is dd/mm/yyyy (e.g., 30/9/2001), however the metric date format of YYYY-MM-DD is also officially accepted. This is the recommended short date format for government publications. The first two digits of the year are often omitted in everyday use and on forms (e.g., 30/09/01).

The common long date format is, for example, "Friday, 1 January 2010", as is found on all Australian Government documents and on their websites, including the majority of non-government documents. However, the alternative long date format of "Friday, January 1, 2010" may also be found, predominantly in newspapers such as The Australian or The West Australian. As in the UK and New Zealand, the date is read either as "the first of January" or "January the first", and this reading is acceptable in the Australian military.

Weeks are most often identified by the last day of the week, either the Friday in business (e.g., "week ending 19/1") or the Sunday in other use (e.g., "week ending 21/1"). Week ending is often abbreviated to "W/E" or "W.E.". The first day of the week or the day of an event are sometimes referred to (e.g., "week of 15/1"). Week numbers (as in "the third week of 2007") are not often used, but may appear in some business diaries in numeral-only form (e.g., "3" at the top or bottom of the page). ISO 8601 week notation (e.g., 2007-W03) is not widely understood.

Time

The 12-hour notation is the most common in Australia. The 24-hour clock is widely understood, and commonplace in technical fields such as aviation, computing, navigation, and the sciences. It is also commonly used in consumer electronic equipment such as video recorders, reticulation controllers etc. The before noon/after noon qualifier is usually written as "am" or "pm". A colon is the preferred time separator .