age

Always use Arabic numerals for people and animals. Use standard number rules for inanimate objects, companies, etc.

• The tiger is 8 years old.
• They turn 101 years old this September.
• Crayola, the best-known maker of children’s crayons, turned 100 years old in 2003.
• The garden is only three years old.

Exception: if starting a sentence with an age, spell out the number instead of using Arabic numerals.

• Eight-year-old Sara is good at math.
• One-hundred-and-one-year-old Max was a pilot during World War I.
• One-hundred-and-twelve-year-old Crayola is the world’s leading children’s’ crayon maker.

Because of how complex the sentences and words read, it is best to reword the sentence so it does not start with the age.

Hyphenate with “years old” when using age as an adjective.

• My three-year-old garden was built using permaculture techniques.
• The 8-year-old tiger is very playful.
• The 101-year-old former political stalwart gave a rousing speech.
• Century-old Crayola is still dominant in the crayon market.