Numbers

When to use digits or words

Numbers written as digits are generally easier to read and understand.

When writing numbers, use:

• digits for numbers 2 and above
• words for numbers ‘zero’ and ‘one’.

The numbers ‘0’ and ‘1’ are difficult for some users to read. Some typefaces make it hard to distinguish between the digits ‘0’ and ‘1’ and letters such as ‘o’, ‘l’ or ‘7’. Writing ‘zero’ and ‘one’ reduces the risk of confusion.

Exceptions

There are situations where writing numbers as words improves readability, while in other cases digits provide greater clarity or precision.

The choice depends on the context, the audience and how easily the information can be understood.

Big numbers

When writing large numbers:

• use commas to separate thousands when the number is over 999
• combine a number with the word ‘million’ for figures over 999,999 — unless the number needs to be written in full (for example, in technical data)
• do not abbreviate ‘million’ as ‘m’.

Apply the same approach for ‘billion’, ‘trillion’ and so on.

Ordinal numbers

Ordinal numbers indicate the order or position of something — such as first, second or third.

• Write ordinal numbers from first to ninth as words.
• Use digits with a suffix from 10th and above.

Exceptions to using words for ordinal numbers

• Do not use ordinals in dates.
• Centuries always use digits, even under 10.

Dates and times

• Write dates as day, month and year in full.
• Do not use ordinal numbers, for example, 1st or 3rd, in dates.
• Show time using a 12-hour clock.
• Show start and end times in full.
• Use ‘midnight’ not ‘00:00’.
• Spell out the names of days and months in full.
• Use ‘to’ instead of an en dash (–) in date and time ranges as it’s easier for screen readers to read out.

Phone numbers

• Always use ‘freephone’ (not phone) for numbers that are free to call, such as an 0800 number.
• If it’s a New Zealand freephone, always put ‘(NZ only)’ after the number.
• Use cellphone, rather than cell-phone or cell phone.
• Use ‘TTY’ as the label for any number that provides a text service for the deaf community.
• Unless they’re used in the middle of a sentence, phone and freephone should always have a colon after them.

HTML code for phone numbers

• Mark up phone numbers as links so people can tap or click to call.
• Use a non-breaking space to separate parts of a telephone number. This keeps the number together on one line.

<a href="tel:+64045558080">04 555 8080</a>

<a href="tel:+64034447777">+64 03 444 7777</a>

<a href="tel:0800555222">0800 555 222</a>

Currency

Where the content is only talking about New Zealand dollars, use ‘$’. If users could be confused about the currency being referenced, use NZD$.

For other currencies, use the country prefix followed by the relevant symbol for that currency.