When to Use a Hyphen

By eContent Pro on Jan 24, 2017
When to Use a Hyphen

A hyphen is a commonly used punctuation mark, although its proper usage is often misunderstood. The primary function of a hyphen is to glue words together by showing their relationship.

When Should You Use a Hyphen?

To create a compound adjective

A compound adjective is two or more words that come before a noun and modify it as a single thought. Some examples of compound adjectives would be:

  • Chocolate-covered
  • Hands-free
  • All-star

If these compound adjectives were used in a sentence after the noun, they would not need to be hyphenated. Examples:

  • Are those strawberries chocolate covered?
  • Does this car have the option to talk hands free?

Some well-established compound adjectives are always hyphenated, such as our all-star example.

  • He’s an all-star runner.
  • That runner is an all-star.

If you are using a new, original, or unusual compound noun, you will want to use a hyphen to avoid any possible confusion.

  • She is an avid book-reader.
  • He is a serious video-gamer.

To show a period of time, such as an age

You can use a hyphen to help distinguish any periods of time that you may have in your writing.

  • My coworker has a four-year-old child.

You will also want to be sure to always include the second hyphen in this case. Without the second hyphen, this sentence becomes about an old child.

  • My co-worker has a four-year old child.

When writing about years, months, or any other period of time, be sure to use hyphens unless the period of time (years, months, weeks, days) is written in plural form.

  • Their child is four years old.

Rules for Using Hyphens

Do not interchange with dashes

When using a hyphen, you will want to ensure that you are using a hyphen and not a dash. The hyphen can be found on most standard PC keyboards as the bottom symbol on the key between the 0 and the = sign.

No spaces around hyphens

When you are using a hyphen in your writing, you will want to be sure that you are not putting spaces before or after the hyphen in your sentence.

  • Incorrect: Chocolate – covered strawberries.
  • Correct: Chocolate-covered strawberries.

The adverb “very” and adverbs ending in “-ly” are not hyphenated

With this rule, you cannot use the word very or an adverb that ends in -ly as part of any compound adjectives that would need to be hyphenated. An adverb is defined as: a word or phrase that modifies or qualifies an adjective, verb, or other adverb or a word group, expressing a relation of place, time, circumstance, manner, cause, or degree (e.g., gently, quite, then, there).

  • Incorrect: A very-happy dog.
  • Correct: A very happy dog.
  • Incorrect: This car is a finely-tuned machine.
  • Correct: This car is a finely tuned machine.

Don’t hesitate to add a hyphen if it prevents a misunderstanding

If you are not sure whether you should add a hyphen to your writing, and you believe that your phrasing will cause a misunderstanding, feel free to add the hyphen. We have listed some additional examples of when you should add a hyphen below:

Hyphenate a prefix that ends in a vowel when the root word begins with the same last letter for clarity

If you are using a prefix in your sentence, and the root word begins with the last letter of the prefix, hyphenate the word.

  • Incorrect: Extraambitious
  • Correct: Extra-ambitious

Use a hyphen with the prefix re- when omitting the hyphen would cause confusion with another word

If you are using the prefix re-, and the final word could be confused with another existing word, you will need to add a hyphen to show which word you mean.

  • Incorrect: I need to recover the bedroom furniture before they start painting.
  • Correct: I need to re-cover the bedroom furniture before they start painting.

Hyphenate a prefix when you feel a word might be distracting or confusing without the hyphen

If you believe that your word will be jumbled or lose some of its intended meaning without including a hyphen, then you can add one without breaking any writing rules.

  • Incorrect: We sat on the plane for deicing for an hour.
  • Correct: We sat on the plane for de-icing for an hour.

Hyphenate all compound numbers from 21 to 99, all spelled out fractions, and don’t hyphenate fractions introduced with a or an

You will need to put a hyphen into any compound numbers or spelled out fractions.

  • Incorrect: There are fifty seven kids in that grade.
  • Correct: There are fifty-seven kids in that grade.
  • Incorrect: They need two thirds of the vote to win.
  • Correct: They need two-thirds of the vote to win.

You will want to be sure that you do not include a hyphen in any fractions that are introduced by “a” or “an”.

  • Incorrect: It’s one-third of a mile down the road.
  • Correct: It’s a third of a mile down the road.

Don’t hyphenate multiple-word proper nouns when used as compound adjectives

When you are using a proper noun that consists of two words, you should not include a hyphen.

  • Incorrect: She attends Ohio-State University.
  • Correct: She attends Ohio State University.

Hyphenate prefixes before proper nouns or adjectives

  • Example: The party is planned for mid-August.

Hyphenate all words beginning with the prefixes self-, ex- (in this case, meaning former), and all-

Examples:

  • She is now self-employed.
  • My ex-classmate took my notes.
  • We are going to an all-inclusive resort.

Final Thoughts on Using Hyphens

Ultimately, when you are confused about whether to use a hyphen, you should look up the word that you are trying to use. If you are still confused, let us help you. eContent Pro has professionally trained copy editors who will review your document for correct hyphen usage, as well as a multitude of other writing problems. Learn more about our copy editing and proofreading services.

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