Traditionally no, when using an em dash for a ‘self-interruption’, there should not be spaces either side of it.
This is how it’s traditionally done, and if you look through a lot of older texts, this is how you’ll see it. However, this can look a bit cramped on the page, and because the dash almost connects to the word either side of it, it can look like an absurdly long hyphen, which can interrupt reading flow.
Some people do put spaces either side of an em dash, but then this tends to take up a lot of space on the page. If you want to have spaces either side of the dash, it’s better to go with the en dash, which is a dash half the width of an em dash.
In a formatted book, hyphens should never be used for this purpose – even though when typing online, this often is the typographical mark that we use, because the hyphen is on the standard keyboard, whereas the en dash is not. If you’re using a word processor like Microsoft Word, as you type, in its default settings, it will replace and ‘ – ‘ with an en dash for you. Many programs and applications will also replace a double hyphen with an en dash (and a treble hyphen with an em dash).
← Writing FAQs