Plural Rules: 5 Simple Rules Every Student Should Know

Without even thinking about it, we make words plural every day. We might go to one grocery store or visit several stores. Most of the time, making a word plural is as simple as adding -s.

• cat to cats
• book to books
• store to stores

But what happens when the word doesn’t follow that pattern? Why do we write watches, stories, leaves, or children instead?

Fortunately, students don’t have to memorize every plural word. By learning a handful of spelling patterns, they can spell most plural nouns by using rules.

Let’s look at the five plural rules commonly taught in structured literacy and Orton-Gillingham.

In dividing plural rules, we have five categories.

CH, SH, S, X, Z Plural Rule

When a singular noun ends in ch, sh, s, x, or z, add -es.

Examples:

Singular	Plural
watch	watches
bush	bushes
class	classes
tax	taxes
quiz	quizzes

O Plural Rule

Almost all nouns ending in o will spell the plural word by adding an s to the end, including proper names. Examples are radios, pianos, patios, and videos.

Some exceptions to this are a group of nouns that add –es to make the plural.

These are the O Plural Rule words to remember.

• Tomato to tomatoes
• Potato to potatoes
• Torpedo to torpedoes
• Echo to echoes
• Hero to heroes
• Veto to vetoes (low frequency word)
• Embargo to embargoes (low frequency word)

(I did not include vetoes and embargoes in the sentence because they are low-frequency words.)

F to V Plural Rule

Most words that end if f or fe become plural by adding an s. Words like, cliffs, roofs, and beliefs.

There are some words ending in f or fe that are made plural by changing the fe to v, and adding –es.

Examples:

• knife to knives
• leaf to leaves
• calf to calves
• half to halves
• wife to wives

Four words have two accepted plural spellings: scarf, dwarf, hoof, and wharf. Both forms are considered correct.

• Scarf can be scarfs or scarves
• Dwarf can be dwarfs or dwarves
• Wharf can be wharfs or wharves
• Hoof can be hoofs or hooves

Looking for printable plural rules lessons? Scope & Sequence Workbook 3 includes instruction, word lists, and printable activities for all of the plural rules covered in this article. It’s designed for tutors, teachers, interventionists, and homeschool families who want ready-to-use lessons.

Y Plural Rule

For words ending in y, notice whether there is a consonant or vowel before the y to determine the correct spelling.

If a consonant comes before y…

Change y to i and add -es.

• story to stories
• mystery to mysteries
• baby to babies

If a vowel comes before y…

Simply add -s.

• valley to valleys
• toy to toys
• monkey to monkeys
• chimney to chimneys

Irregular Plural Rule

Most plural words follow a spelling pattern, but irregular plurals are different. Instead of adding -s or -es, the word changes to a different spelling.

Examples:

• child to children
• foot to feet
• mouse to mice
• goose to geese
• woman to women

Irregular words that stay the same

Also known as irregular plurals are words that have the same spelling whether they are singular or plural.

• moose
• deer
• sheep

Special Plural Forms: letters, figures, signs, and words

When making letters, abbreviations, symbols, and some numbers plural, English sometimes uses an apostrophe for clarity.

To form the plural of letters, signs, and words, add an ‘s.

Examples:

• Mind your p’s and q’s.
• There are two A’s in “Aaron.”
• Dot your i’s.
• She earned three 100s on her tests (no apostrophe in numbers).

Style guides differ for decades (1970s vs. 1970’s), but 1970s is preferred in modern writing.

FAQs

What is the easiest way to teach plural rules?

Teach students the most common patterns first:

• Add -s
• Add -es
• Change y to i
• Change f to v
• Learn irregular plurals separately

What are the five plural spelling rules?

1. Add -s
2. Add -es
3. Change y to i
4. Change f to v
5. Learn irregular plurals

Are all words ending in o pluralized with -es?

No. Most simply add -s. Only a small group commonly adds -es.

Is “chimneys” a Y rule word?

Yes. Because the y follows a vowel (e), simply add -s.