How to write dates and times
"What’s the time, Mr Wolfy?"
"Four o’clock"
... or is it 4 pm? Or 4.00 p.m.?
"What's the time, Mr Wolfy?" was a game we played at primary school. But we never had to write it down. What if we did? How would we write it?
It can be confusing when deciding how to write times and dates, especially with so many different ways of doing it.
New Zealand English follows the British system for the most part. Here is an outline of the most accepted ways of formatting dates and times in New Zealand English. Whichever way you choose, remember to stay consistent, either within that document or manuscript, or across your entire organisation's written content.
As always, if your organisation has a different format in their house style, follow that.
Times
Whether you spell times out or use numerals depends on the style of the writing or where the reference to time is being used. Either way is correct.
When the time is vague or it doesn’t matter if it is not exact, you can spell out the words. With o’clock, the number is always spelled out.
At four o’clock in the morning
4 o’clock in the morning ✘
half past four
four thirty
four thirty-five
quarter to four
When the time is specific, numerals are used. There are different ways to write the time in numerals. A colon or full stop is correct (though in New Zealand, a full stop is more common). There is usually a space between the numeral and the am or pm, but not always. As long as it is consistent.
8 am or 8am – no need for the 0s.
10.30 pm or 10.30pm
10.30 p.m. (this is the Oxford Style Manual preference)
However, spell it out in dialogue, even when it is specific.
“He was supposed to catch the train at five thirty-three,” she said.
Twenty-four hour time is shown as:
1200 = noon
2400 or 0000 = midnight
0001 = 12.01 am
1438 – 2.38 pm
At 1500 hours (or 1500h)
Dates
American English usage has been creeping in, with people writing the month and then the date:
On September 12th 2024 ✘
Dates in New Zealand English have the number first, and don't have commas:
On 12 October
On 12 October 2024
In October 2024
A comma is used when the day of the week is added.
Monday, 12 October 2024
If using it in a sentence, there is a second comma after the year.
On Monday, 12 October 2024, we went to Wellington.
Do not use -st and -th with a figure when also mentioning the month.
On 12th August ✘
Monday, 12th August 2024 ✘
On the 12th of August 2024 ✘ (Not in formal writing. OK in informal writing)
We are going on the 12th ✔
Note: superscript is no longer used in writing with ordinal numbers except in mathematical contexts; therefore, do not use superscript for ordinal numbers in dates.
There is no comma in years, unless it is a longer than 4 digits.
2018
10,000 BC
For abbreviations use the format date/month/year.
12/10/18 or 12/10/2018 (for 12 October 2024)
12.10.18 or 12.10.2018
NOT: 10/12/18, as this is the American format of month/date/year.
Decades
Words or figures can be used for decades.
The sixties
1960s (note no apostrophe)
The '60s
In his seventies
In his 70s
Note: in formal writing it is preferable not to use ‘60s.
When speaking of two decades, write both out in full.
1970s and 1980s
1970s and ‘80s ✘
When the name of a decade is used to describe a social or cultural period, use words.
The twenties was the time of flappers and silent films.
The great depression occurred in the 1920s.
Centuries
It is a style choice whether to spell out or use numerals for centuries. Oxford style is to spell out, but in informal writing, it has become common to use figures for centuries.
17th century
seventeenth century
Note: superscript is no longer used except in mathematical contexts.
To abbreviate centuries in notes, references and tables use c. or cent. with a numeral.
14th c.
21st cent.
To use it as an adjective, use a hyphen.
A fourth-century building
An early 17th-century play
A mid-seventeenth-century book
Eras
Use small caps for the BC and AD. The BC goes after the year, and the AD goes before.
c.50 BC–c. AD 20
The c. or ca only refers to the date immediately after it, so needs to be repeated if needed. It is close up if it comes before a numeral, but spaced before words or letters.
When spelled out, the AD should be after the words.
In the third century AD
Date ranges
When writing date ranges, use an en dash, not a hyphen.
1999-2000 ✘
1999–2000
Dates that cross a century or are specific dates of a person’s birth and death should not be elided.
1698–1703
1698–03 ✘
A range in BC should always be in full to prevent confusion.
175–22 BC (cf. 175–122 BC)
65–8 BC is 57 years, not 3 years.
When describing a range, use the from … to … format, the between ... and ... format, or an en dash. Be careful not to blend the three formats.
The period from 1989 to 1999
The period 1989–1999
The period from 1898–1999 ✘
The period between 1989 and 1999
The period between 1989–1999 ✘
At the start of a sentence
Just as all numbers should be spelled out at the start of a sentence, so should years. But it's better to rewrite the sentence.
1856 was a difficult year. ✘
It was a difficult year in 1856.
Eighteen fifty-six was a difficult year.
What next?
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Sources:
Hughes, J., & Wallace, D. (2010). Fit to Print : The Writing & Editing Style Guide for Aotearoa New Zealand. Wellington, New Zealand: Dunmore Publishing.
Chicago Manual of Style
Oxford University Press, (2016). New Oxford Style Manual (3rd ed.). United Kingdom: Oxford University Press.