In writing, there are three main dashes you come across: a hyphen (-), an en dash (–), and an em dash (—). I’ve seen writers confuse them all the time.
However, these are easy fixes. It’s all about understanding the difference between them.
A hyphen (-) is the most common and goes between words to join them together. For example, up-to-date, self-knowledge, and life-size all have hyphens.
An en dash (–) is a little longer than the hyphen. It’s named after being about the length of the letter N. They are between related words that have a distance between them. For example, January–May. There are many months between January and May, so it gets an en dash.
They are mostly known for separating numbers though. (Think of N for numbers.) For example, pages 197–359 or years 2005–2018.
Another way of looking at it is that an en dash specifies a range of things. The range of months or the range of numbers.
An em dash (—) is my favorite and has multiple meanings.
The most common way to use an em dash—as I’ll show in this sentence—is to break up information. It’s like using parentheses or commas, but it feels cleaner to me. It’s almost as if the parenthesis takes the reader to the side for a second while the em dash pauses to let the reader know more information.
Commas in sentences, like here, are more common and work well too. Em dashes can replace them, but be careful. Em dashes are like sprinkles on a cake. You only need a handful to decorate. You don’t need to put them everywhere and cover the entire cake.
I also use em dashes for interrupted speech or a break in thought.
“What else would I—”
It wasn’t like humans had their own magical pendant that gifted them— Unless they were the reason for the missing pendants.
I hope this helps see the difference between the three!