The following is a reader submission.
How do you write out the age of a person? Is it correct to write: 48-year-old or 48 year-old?
Hi Amy,
Thanks for the great question. It’s actually a pretty simple answer.
If you use the phrase as a noun, you use hyphens (e.g. The 48-year-old ate at the diner). If you use the phrase as an adjective, you omit the hyphens (e.g. The diner’s patron was 48 years old).
I hope this clears it up for you.
Kim
Update (9 Sep 2015): As suggested by Kerry Lewis, you also hyphenate when using a compound adjective:
You also hyphenate it when it's a compound adjective: the 48-year-old man. #punctuation #grammar #SPaG https://t.co/kzqKxPQ6Wx
— Mrs SPaG (@Mrs_SPaG) September 9, 2015
Email me your grammar questions. I’ll be sure to post the question and answer here.
Can it not also be used hyphenated as an adjective? Consider this statement:
The 48-year-old man ate at the diner.
I think it depends on how the adjective is used. If the adjective is optional, as in my sentence (it would still make sense to say “The man ate at the diner.”), then you would still hyphenate.
In your example above, you wouldn’t hyphenate because the sentence would make no sense without the adjective (“The diner’s patron was.”), unless you were speaking existentially. ;)
I’m sure there’s a term for the varying usages of adjectives in this regard, but I’m not familiar with those terms.
Good point, Ben.