If you’re like me, adding ’s to the end of a word that already ends in an s to make it possessive is almost a physically painful experience. It’s not what I was taught, and it just looks wrong! But the rules have changed over the years, so I must—begrudgingly—teach you the new ways.
If a word is plural and ends in an s, then you can still just add an apostrophe to make it plural.
He was going to go for a walk, but he couldn’t find the dogs’ leashes.
While my apartment is being fumigated, I’m staying at my parents’ house.
But if the word is not plural, then you add ’s to make it possessive, even if it already ends with an s.
I love Doris’s new hairdo.
The Mercedes’s driver was extremely unhappy when the shopping cart rolled into the side of his car.
To me, this looks especially ridiculous if the word ends with ss.
Have you seen Jess’s new baby? She’s so cute!
The business’s new owner expects to double the company’s size in less than a year.
Note that you do not use ’s to pluralize numbers, only to make them possessive. So, when you see a sign for a new neighborhood with “From the 200’s,” that’s wrong.
That dress looks like it’s right out of the 1850s.
2016’s election promises to be interesting.
Letters used as letters, on the other hand, are pluralized with ’s if they are lowercase. Note that the letter is italicized, but the ’s following it is not.
Do you spell your name with two e’s or one?
I made all As in college.
If you, however, are of the same mind as I am and prefer to use the former practice of “Doris’s new hairdo” and “Jess’ baby,” let your editor know this is your preferred style before editing begins. I will certainly accommodate!