What is the en rule?

The en rule, also known as the en dash, is one of the most underused punctuation marks in the English language.

As ridiculous as it might sound – I mean, I do realise we’re taking about a punctuation mark here – I can’t help but feel a bit sorry for the en rule; often mistaken for a hyphen, many people haven’t even heard of it.

So, let’s put the record straight.

The en rule is a horizontal dash. It is so called because the length of the dash is said to be the same as the letter N.

The en rule has several main functions:

1. To indicate ranges of numbers, dates, months of the year, etc., e.g. 1939–1945.

2. To connect two words of equal importance that are used to describe something else, e.g. parent–child relationship.

3. To join the names of co-authors or co-creators, e.g. the Lloyd-Webber–Rice musical.

4. As a more informal alternative to a colon or brackets or to separate a word or a phrase from the rest of the sentence. For example, 'I've seen it all − the good and the bad.’ (You can also see how I’ve used it in this way in the second paragraph of this article).

US English, and some styles of British English, use an em rule here instead which, you guessed it, is about the same length as the letter M (—).

As a proofreader and copyeditor, the most common mistake I come across is writers using a hyphen instead of an en rule.

An en rule is NOT a hyphen.

1-100 = WRONG!

1–100 = CORRECT!

We all knew the verdict - guilty. = WRONG!

We all knew the verdict – guilty. = CORRECT!

Times may have changed, but I certainly wasn’t taught about the en rule at school. Probably because this particular punctuation mark only applies to typed text, not handwritten (imagine how painstaking it would be if we had to start measuring every hyphen and dash we wrote by hand!).

How to add an en rule in MS Word

Type it. There is no en rule button on your keyboard. However, if you type your word followed by [space] [hyphen] [space] next word [space] then as soon as you type that final space, MS Word will automatically change the hyphen into an en rule for you.

Insert it. If you are using it within a range or to link two words, which doesn’t involve a space either side, then you can add it via the Insert function on your tool bar:

Insert → Symbol → Special Characters → En dash

If you want to, from there, you can create your own shortcut for regular use.

Mac users can use the ‘Option’ key + hyphen.


New Hart’s Rules: The Oxford Style Guide, 2nd ed. (2014) Oxford: Oxford University Press