A hyphen is a small dash and this one is the most frequently used. It is the smallest of the three. It is mostly used to join words together. A simple example is joining two words before a noun, such as in the following examples.
‘John drove down a one-way street.’
’He was looking for house number twenty-five, where his step-sister had resided for thirty-two years.’
A hyphen can be used to join compound numbers (as shown above), and also for prefixes such as: ex-, self-, and all-.
‘Joan did not want to meet her ex-husband, as her self-confidence was at an all-time low.’
It is important to avoid mistaking a hyphen for an en dash. The en dash is slightly longer than the hyphen. If you are using Microsoft Word, the en and em dashes can be found by clicking the Insert tab and then clicking Symbols.
En dashes are usually used to indicate range instead of the word ‘to’, to highlight a relationship, or contrast values.
Here are some examples:
‘John knew the drive would take 2−3 hours.’
‘The essay should be 500−550 words long.’
‘To qualify for a pass in the exam, 70−80 points were required.’
Students and academics will use en dashes most commonly in page ranges in their references. For example, a Harvard in-text reference would look like this: (Lines 2010, pp. 69−72).
Em dashes are approximately the length of the letter m and can be used at the end of, or in the middle, of a sentence. Em dashes are usually used to set off a parenthetical thought, to display an interjection, or to amplify or explain an element.
Here are a few examples:
‘John was proud of himself—he had received 90 points in his exam.’
‘Joan was devastated—having just received her results—only achieving 65 points.’
‘Betty was resigning from her job—she had won the lottery.’