Style basics
Always use numerals, but only hyphenate if the age comes before a noun
As with other numbers, the ASG recommends using numerals to show ages.
Jacky turns 30 today.
It’s Jacky’s 30th birthday.
Jacky turns thirty today.
‘One’ is the only age to take care with, if you think the numeral might be lost in your body text.
The more common uncertainty is when to hyphenate ages in a sentence. Use hyphens if:
- you’re using an age as a compound adjective before a noun
- the age forms a single noun that is acting as the subject or object in a sentence.
A 17-year-old student is raising global awareness of climate change.
A 17-year-old is raising global awareness of climate change.
But if the adjective comes after the noun, leave out the hyphens.
The student who is raising global awarenesss of climate change is just 17 years old.
Key tip: if you’ve used the plural ‘years’ in a phrase, you can leave the hyphens out.