How To Use Apostrophe S

One question I get asked on the regular is how to use apostrophe s in plural or possessive form.

Misuse of plural s, and apostrophe use, are a couple of the most common mistakes people make regardless of their writing skill. It’s actually very rare for me to proofread a piece of content without coming across either of these issues.

In this post I’ll:

  • point out the most common mistakes people make
  • review how to use s in plural form
  • go over apostrophe use
  • Plus, there’s a handy cheat sheet for you to print out!
How to use possessive s


The Most Common Mistake People Make With S

It’s instead of Its, or vice versa
Hands down, this is the number one mistake everyone makes. It’s easy to overlook when you’re in a rush, but for most people it’s a case of not understanding the difference between the two.

To clarify:
It’s is a contraction of it is. Example: I wanna know what it’s all about.
Its is possessive. Example: The dog grabbed its bone from the cat.

I always tell people to use the “It’s/Its” test when they’re on the lookout for a legit proofreader. If they find more than one incorrect use of its or it’s on the proofreader’s site, then chances are they’re untrained and only have a layperson’s knowledge of proofreading/language.


You’d think making words plural is pretty basic. I mean, you just add s to the end of a word, right? But many people struggle with this; they think they need an apostrophe.

How many times have you seen something similar to this in public?

On sale: apple’s, orange’s, and banana’s.  (I know, SO wrong.)

And how many times were you tempted to break out your pen so you could change it to this?

On sale: apples, oranges, and bananas. 

We were all taught in grade school that to make a noun plural we just add ses or ies to the end of a word. Here’s a quick recap of how to make words plural.

Suzy had a kitten. Suzy had four kittens.

When a singular noun ends with an s, sh, ch or x we then add es.

Sam wants a sandwich for lunch. Sam wants two sandwiches for lunch.

You also add an es when the word ends in an o.

I need a tomato for this salad. I need three tomatoes for this salad.

Note: not all words that end in o use an es for plural form, like the word ratio. If you’re unsure, check with your dictionary.

If a word ends with a y, then ies replaces the y to make it plural:

Taking care of one baby isn’t overwhelming. Taking care of three babies is overwhelming!

Of course, you can’t forget irregular plurals like:

Goose Geese
Child Children
Leaf Leaves
Knife Knives

More Than One Plural Form

If your dictionary shows more than one spelling for the plural form, then use the first form mentioned, which is an industry practice.

For example, Merriam-Webster’s Collegiate Dictionary gives two variants for the plural of fish: fish and fishes.


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Proper Nouns

To make the names of people or capitalized nouns plural you simply add s or es:

My favorite day is Sunday. I love Sundays.
Mr. Jones went camping with his family. The Joneses went camping.

Apostrophe S To Show Possession: ‘S

Things start to get a little hairy when it comes to possessive s, especially when a word is plural or already ends in s.

When it’s a singular noun it’s pretty straightforward:

Sally‘s bootcamp doesn’t run on weekends.
(The ‘s after Sally shows that the bootcamp belongs to her.)

If a singluar noun already ends in s, add ‘s:

Miles‘s car was stolen today.

How about if a name already ends in apostrophe s, like McDonald’s? In this case there are 3 options:

You can add ‘s to the end: The McDonald’s‘s parking lot was packed.
This looks really weird, yeah?

It’s acceptable to use just an apostrophe: The McDonald’s’ parking lot was packed.
Ok, this looks a bit better than option 1.

Or you could not use anything at all: The McDonald’s parking lot was packed.
This is my preferred style. Doesn’t it just look and read better?

Remember, any of these three choices are fine, as long as you’re consistent.

If you’d like to grab the handy cheat sheet, sign up for my free Proofreading Resources Pack. 

To make plural nouns that already end in s possessive you add an apostrophe at the end like this:

The students phones were held by the teacher during the test.
The Joneses tent can hold 10 people.

If the plural noun is spelled differently then you add ‘s:

The men‘s club is very exclusive.


As a proofreader, you’ll encounter some kind of issue with plural and possessive s in almost every piece of content you work on.

What other spelling/grammar mistakes do you see a lot of that drives you crazy? Let us know in the comments below! 

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