Let's talk about the difference between the en dash and the em dash. They sound very similar and look very similar but they are used in different ways. So the en dash looks like this (en -).
It is about the width of the letter n. The em dash looks like this (em --) and it's about the width of the letter m. So that's how they get their names. Now how do we use them? We use the en dash in place of the word to. Oftentimes when we are talking about dates. So we might say from the years 200l to 2003 (2001-2003).That right there is the en dash. (She points to the dash between 2001 and 2003.) It is not the hyphen, it is not an em dash. It is that in between length of a dash called the en dash. You can also use it by saying January to March (January-March).
Again the en dash is replacing the word to. It is kind of a short hand. Another way that you can use the en dash is if you're talking about a border perhaps.Say you want to say the Arizona Texas border, (Arizona-Texas) the en dash works well there too. We use an em dash, the longer dash, a different way. Essentially, it is a form of pause punctuation that can take the place of a comma, a semicolon. an ellipses. It is a way to set some information off in our sentence and say this is extra important or perhaps this isn't a side. Here is one example: You are my friend--My best friend-- in the world.
So you can see how we have used the em dash to set off this information. It is not necessarily critical to the meaning of the sentence but it is some extra information and it adds emphasis.So the em dash can be really good for drama. In the past it has been frowned upon in formal writing but I think it is becoming increasingly popular in informal writing and in magazines, newspapers and essays. So you might find yourself using the em dash more and more.