Use the format “aged [age] years”
aged nine years
Use the format “aged [age] to [age] years”.
aged 10 to 11 years
Include the months or weeks for ages under a year.
aged nine weeks
If you refer to ages as “[age]-year-old”, include the hyphens.
16- to 24-year-old men
Write decades as an age as numerals.
women in their 40s
Limits for age restrictions should use “aged [age] years and over” or “aged under [age] years”. Don’t use the plus sign.
aged 75 years and over
aged under 18 years