In Australia, time in written text usually uses the 12-hour clock:
8 am or 8 pm [no stops in am or pm] not 0800 or 8 o’clock
7:30 am
To avoid confusion, do not use am or pm when referring to noon and midnight:
12 noon 12 midnight
12:01 am [1 minute past midnight]
12:01 pm [1 minute past noon]
Spell out all units of time, and use numerals rather than words for numbers:
10 seconds 5 minutes 24 hours 14 days 1 week 3 months 4 years 5 L/min
The rule to spell out units of time can be relaxed in tables if it is critical to save space, but avoid confusion with other units:
10 s 5 min 24 h 14 d 1 wk 3 mo 4 yr
The abbreviation for year can be either y or yr; maintain consistency within the publication.
For parts of hours, minutes and seconds, close up the values:
2h40min not 2 h and 40 min
or use decimal fractions:
Like other units, abbreviations of units of time are not written with a full stop, nor do they take a plural s when referring to numbers greater than 1.
