When should I use a hyphen between two words?

A hyphen is a bit of punctuation used to join two (or more) different words. There are 4 situations in which you should use a hyphen between two words:

1) In numbers between 21 and 99 (twenty-one)

2) With some prefixes (self-motivated)

3) Between many compound words (life-size)

4) For clarity (de-ice)

When you use two words together as a single thought describing or modifying a noun and you put them before the noun, you should hyphenate them. For example:

• there's off-street parking here
• chocolate-covered raisins
• this is a family-owned business
• small-town charm

You also use hyphens between two words if they belong to the following categories:

Numbers 21 through 99

You need a hyphen when writing out numbers twenty-one and ninety-nine, and everything between.

Some prefixes

Normally, prefixes don't need hyphens, but they do when the word is a proper noun or particularly long to begin with:

• Place your order pre-Christmas to enjoy our discount.
• There's an enormous problem with under-representation of minority groups.

We always need hyphens with the prefixes anti- and self-:

• I'm a self-motivated person.
• Move in an anti-clockwise direction.

For clarity

Hyphens can be used to clarify confusing or awkward combinations, like shell-like or de-ice.