A lot of people are unsure of how to correctly use an apostrophe. In this post things are made a lot clearer.

When dealing with a singular noun, put the apostrophe before the s.

Example sentence: I borrowed my friend’s car for my driving test.

When dealing with a possessive noun that ends with s, put the apostrophe after the s.

Example sentence: Chris’ car was badly damaged in an accident over the weekend.

When dealing with a plural noun ending in s, put the apostrophe after the s.

Example sentence: The students’ marks were well below the state average.

When dealing with a contraction, put the apostrophe where the letter has been removed.

Example sentence: I don’t understand how some people can go days without sleeping.