Ordinal numbers

Ordinal numbers show the order in a set, such as:

  • 1st, 2nd, 3rd
  • first, second, third. 

Cardinal numbers, on the other hand, show how many of something there are (1, 2, 3).

The key style question for ordinal numbers relates to when to use numerals (1st, 2nd, 3rd) and when to use words (first, second, third). This usually depends on whether you are using them as an adjective or an adverb. But always use words for ordinal numbers in common expressions or idioms.

Adjectives
Use numerals, without superscript
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Most ordinal numbers will be adjectives that describe a noun. Present these as numerals rather than words.

If your word processor autocorrects the ordinal to display in superscript, change it back to standard type and try to update your autocorrect settings. Superscript is much harder to read.

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75th anniversary

If the ordinal forms part of a compound adjective before a noun, you shouldn't need a hyphen as long as there’s no chance it could be misread.

18th century manuscript
Adverbs
Use words
First, we found that ...
Please sign in at reception first.

For ordinal numbers used as adverbs in body text, spell the word out. In these cases, the adverb is helping to show the structure of a series of sentences rather than the order of a single noun, and it will often occur at the start of the sentence.

Although it operates as an adverb, you can use the ordinal form without adding the extra ‘ly’ that adverbs of manner take.

First, we will set out our recommendations.
1st, we will set out our recommendations.
Firstly, we will set out our recommendations.
Common expressions
Use words
This is first class!
It is second nature to him.
See also:   Cardinal numbers,  Hyphens -,  Numbers,  Ordinal numbers,  Years