The apostrophe is the most commonly misused punctuation mark. There are two uses for apostrophes:

Contractions are words where one or more letters have been omitted. The apostrophe is used in place of the letter(s) that have been removed. Some of the most common examples are:

Contractions can be used in formal writing, but you should use them only rarely as they make writing more chatty.

Some words feature an apostrophe because they were once contracted, but now we only ever use the contracted form:

Possessives indicate that something belongs to someone. The place of the apostrophe depends on whether the possessor is singular or plural. A singular possessive goes before the possessive 's'; a plural possessive goes after the possessive 's'.


Some people find it helpful to think of possessive apostrophes as showing something has been left out. The apostrophe takes the place of the missing word.

However:

N. B. the possessive 'its'

The possessive 'its' causes endless confusion with apostrophes. ‘Its’ is the possessive form of ‘it’. It does not need an apostrophe. It operates just like his and hers, which don't take apostrophes:

'Its' takes an apostrophe only when it's a contraction:

The incorrect use of apostrophes irritates markers, mainly because it's really quite easy to get them right.