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Hyphen Usage with Ages (with Examples)

Hyphens in Ages

This page explains the rules for using hyphens in ages.

Hyphens in ages appear in three forms:

The "Compound Noun" Form

Here are some examples of the compound-noun form:
  • He is a two-year-old with attitude.
  • (This is a compound noun. (It is just like words like ice-axe or cooking-oil, which are also compound nouns.) The words in a compound noun are linked together to show they are a singular entity.)
  • I look after three two-year-olds from 9 am to 11 am.
  • (As with most nouns, there is a plural version too.)
The compound-noun form stands alone. It does not modify the word that follows.

Read more about compound nouns.

The "Compound Adjective" Form

Here are some examples of the compound-adjective form:
  • He is a two-year-old horse.
  • (This is a compound adjective. It is no different from word an adjective like two-page in two-page document.

  • I look after three two-year-old horses.
  • (As with most adjectives, it can modify something singular or plural.)
The compound-adjective form does not stand alone. It modifies the word that follows (horse and horses in the two examples above).

Read more about compound adjectives.

The "Predicate Adjective" Form

Here are some examples of the predicate-adjective form:
  • Jason is two years old.
  • (The predicate-adjective form appears after a linking verb (here, is) and after the noun it modifies (here, Jason). There is no need to use hyphens in the predicate adjective form.)
  • Jason is twenty-two years old.
  • (This version contains a hyphen only because twenty-two is spelt with a hyphen under the rules for writing numbers in full.)
Read more about predicate adjectives.
Top Tip

Simpler Rules for Hypens in Age Terms

Here are some simple rules for using hyphens with ages:

(1) There is never a hyphen after the word old.

(2) There is never a hyphen before or after the word years (Note: This rule applies only to years not year.)

(3) There are always hyphens around the word year (provided it's not in a predicate adjective following a or one).

Of course, someone could concoct an example or two to undermine these rules, but if you're struggling to understand compound nouns, compound adjectives, and predicate adjectives, these rules will see you right.