Follow Australian conventions for dates

Australian style conventions apply to dates expressed in numerals and words, and in numeric formats. 

Months and days

Months and days are proper nouns, so they start with an initial capital.

Use abbreviations only if space is limited, for example, in tables, illustrations, charts and notes. Ensure it is obvious to users which months or days you are referring to. 

The standard abbreviations for the days of the week are:

• Monday – ‘Mon’ or ‘M’
• Tuesday – ‘Tues’ or ‘Tu’
• Wednesday – ‘Wed’ or ‘W’
• Thursday – 'Thurs’ or ‘Th’
• Friday – ‘Fri’ or ‘F’
• Saturday – ‘Sat’ or ‘Sa’
• Sunday – ‘Sun’ or ‘Su’.

The standard abbreviations for the months are:

• January – ‘Jan’
• February – ‘Feb’
• March – ‘Mar’
• April – ‘Apr’
• May – retain as ‘May’
• June – retain as ‘June’ or shorten to ‘Jun’
• July – retain as ‘July’ or shorten to ‘Jul’
• August – ‘Aug’
• September –  ‘Sept’
• October – ‘Oct’
• November – ‘Nov’
• December – ‘Dec’.

Use the shortest form of days and months – ‘F’, ‘M’, ‘N’ and so on – only in limited applications, such as time-series charts.

Full dates

In general, use numerals for the day and the year but spell out the month in words. Don’t include a comma or any other punctuation. When using full dates, don’t use ordinal numbers.

Don’t shorten dates in text.

Incomplete dates

Spell out the month in words when you need to leave out either the day or the year.

If you are referring to a date but not specifying the month, use a number with a suffix (an ordinal number). Don’t put the suffix in superscript.

Numeric dates 

Avoid writing dates entirely in numbers. It can be confusing because different countries have different conventions. Use numeric dates only in tables or when space is limited.

The order of the day, month and year differs between countries:

• In Australia and the United Kingdom, the sequence is day, month, year – for example, 7/12/2020.
• In the United States and some other countries, it is month, day, year – for example, 12/7/2020.
• In Sweden, it is year, month, day – for example, 2020/12/7.

Use Australian style unless you are preparing content for an audience in another country that uses a different style.

Slashes and full stops

Separate the numbers in a numeric date with an unspaced slash, using the format ‘day/month/year’. This format uses single digits for single-digit days and months.

A full stop is used in many computer systems and applications. Use the format ‘dd.mm.yyyy’, which uses 2 digits for all days and months.

If the content uses a mix of sources of dates, check your organisation’s style guide for the preferred style and apply it consistently.

Two digits

You can also use 2 digits for each element.

Use this style for the year only:

• in financial data
• if it is clear which century you are referring to.

Whichever style you use for date formats, use it consistently.

Use ‘from’ and ‘to’ in spans of years

Avoid en dashes in spans of years. Write the years out in full.

The exceptions are:

• financial years
• information in parentheses, such as terms of office and years of birth and death.

For these, use an en dash without any spaces on either side.

Don’t use an apostrophe for decades 

Write the span of decades with an ‘s’ on the end. Do not use an apostrophe.

In more casual writing, you can use expressions such as ‘the eighties’ or 'the '80s' (using a contraction for the missing numerals in the year).

Refer to specific days, events and periods with capitals

Most references to specific days, times of year or periods in history involve proper names. Use initial capitals for proper names, except for any prepositions.

Generic terms – such as seasons that occur each year – use lower case.

Holidays and events

Use initial capitals for all institutional holidays, religious days and public events.

Periods and events of historical importance

Use initial capitals for specific periods and events of historical importance, but not when you abbreviate them to a generic term.

Australian style for the world wars is to spell out the number of the war and use initial capitals for each word. American style uses upper case roman numerals.

In content with many references to the world wars, write them out in full the first time you use them. Include the shortened form in parentheses afterwards and use the shortened form throughout the rest of the content.

Eras, periods and centuries

Use initial capitals for the actual name of a geological era or period, but not for broad historical and cultural times.

Use lower case for centuries. Write out the names unless you have limited space. Don’t use superscript for ‘st’, ‘nd’, ‘rd’ or ‘th’.

Use CE and BCE to represent the common era (CE) and the time before the common era (BCE). There is no ‘year 0’ in this system. The years progress from 1 BCE to 1 CE.

Write them without full stops and with a space separating them from the year or century.

Seasons and seasonal events

Use lower case for the seasons and recurrent seasonal events.

Follow conventions for specialised communications and filing

Some systems, such as financial systems and database records, use specific formats for date and time. Check which format you should use.

Date standard for international communication

Use the international standard (ISO 8601:2000) for writing calendar dates for international communication. This sets out a descending order of year (4 digits), month (2 digits) and day (2 digits).

The numbers can be unspaced or separated by a hyphen.

This is becoming more common, especially in software.

Dates for data systems

Use ordinal dates to transfer data among data systems because they’re easy for computers to read.

Ordinal dates consist of 2 or 4 digits representing the year followed by 3 digits representing the day. Days are numbered from 1 to 365 (366 for a leap year).

For example, 7 January 2020 would take different forms using 2 or 4 digits. The last 3 digits remain the same.

If you use dates in electronic data transfer, don’t separate the numbers. If a person, rather than a computer, has to read the information, insert a hyphen between the year and day to make it easier.

Use numbers for the time of day when you need to be precise

In most documents, especially when you need to be precise, numbers give a clearer expression of time.

Use a colon between the hours and minutes.

The use of a colon as the separator reflects a shift in contemporary Australian usage.

The colon avoids confusing people who could misread the time as a decimal number. For example, ‘10.50’ could be read as either:

• 10 and a half
• 50 minutes past 10.

Write ‘o’clock’ only when quoting someone directly or transcribing a recording. Use numerals and the word ‘o’clock’.

Times using ‘am’ and ‘pm’

Use ‘am’ and ‘pm’ in lower case, with a non-breaking space after the number. You can use 2 zeros to show the full hour, but they aren’t essential.

Noon, midday and midnight

Use ‘noon’, ‘midday’ or ‘midnight’ instead of ‘12 am’ or ‘12 pm’ to make it easier for people using your content to be certain of the time.

The 24-hour system

Use the 24-hour system if it helps people understand your content. This is important if you’re referring to time in the context of:

• travel
• some scientific fields
• the armed services.

This system numbers the hours from 00:00 hours (midnight) to 23:59. It always uses at least 4 digits. It can have 6 digits if seconds are included.

• The first 2 digits are the hours.
• The next 2 digits are the minutes.
• The last 2 digits are the seconds, if you include them.

Use a colon to separate the hours, minutes and seconds in 24-hour time.

Time zones

You might also need to define which time zone you are referring to. The Australian zones are:

• CST (Central Standard Time)
• CDT (Central Daylight-saving Time)
• EST (Eastern Standard Time)
• EDT (Eastern Daylight-saving Time)
• WST (Western Standard Time).

Add an ‘A’ (to represent ‘Australian’) to the front if you think it might be confused with a time zone in another part of the world.

This is commonly used in organisations with offices outside Australia. It is also used for international audiences.

Avoid using ‘bi’ to mean either 2 or twice

The prefix ‘bi’ can be confusing:

• ‘Bimonthly’ can mean either every 2 months or twice a month.
• ‘Biannual’ means twice a year.
• ‘Biennial’ means every 2 years.

Instead of using these words, say what they mean.