The most common mistake people will make when using the en dash is accidentally using it in a sentence when they have already set up the dates or times in a way that requires words to be used, not an en dash. If we look at the correct examples from earlier, we’ll show you how we might have written them incorrectly:

1) World War 2 (1939–1945) was one of the most deadly conflicts in history.       (Correct)

2) The 2011–2012 school year was the best one yet!       (Correct)

3) The professor’s office hours are 09:00–11:30.       (Correct)

Above are the correct examples, but let’s look at how we might have written them differently where an en dash wouldn’t be necessary:

1) World War 2 took place between 1939–1945…       (Incorrect)

Because we said that that it took place between the two dates, it wouldn’t make sense for us to put the en dash in here. Instead, we would replace the en dash with the word ‘and’.

2) The best school year was from 2011–2012       (Incorrect)

Again, because we use the term from we have to use the word to in order for it to agree with one another grammatically. Although technically an en dash here would be read as ‘to’ and therefore be correct, it makes little sense to introduce it with words and then switch to an en dash to save time or words in between. So, remove the en dash and put ‘to’ in to make it make sense.

3) The professor’s office hours are from 09:00–11:30       (Incorrect)

Again for the same reasons listed above, using from and to is correct, you choose to either do this or use an en dash; you don’t mix them both together. Replace the en dash with ‘to’.

Another good point to remember about when not to use an en dash is to remember that en dashes should always be between two words or two numbers, without a gap between them. This is because the en dash is used to show connection or conflict, or a span of time, dates, or scores, not as punctuation as part of a sentence as hyphens or em dashes’ might be.