The Rules of Regular and Irregular Plurals

1. For most nouns, just add -s

1.1. file/files, centre/centres, girl/girls, book/books, pen/pens, computer/computers

2. For nouns ending in s, x, z, ch or sh, add -es

2.1. wish/wishes, box/boxes, match/matches, glass/glasses

3. For some words ending in o, add -es

3.1. hero, heroes/ potato, potatoes/ volcano, volcanoes

3.2. Some Exceptions (add -s): kangaroo, kangaroos/ piano, pianos/video, videos

4. For some words ending in f or fe, change the f to a v and add -es

4.1. knife/knives, life/lives, wife/wives, shelf/shelves/elf, elves/loaf, loaves/ thief, thieves

4.2. Some Exceptions (just add s): roof-roofs/ cliff-cliffs/chief-chiefs

5. Nouns that end with consonant + y, change the y to an i and then add -es

5.1. baby, babies/country, countries/ spy, spies

6. Nouns that end in a vowel+ y, just add s

6.1. boy, boys/ day, days/ key, keys

7. Some nouns are the same in both singular and plural from

7.1. deer, fish, sheep,

8. For some nouns, change other letters or just change the word completely

8.1. foot,feet/louse, lice/ man,men/ mouse, mice/ tooth,teeth/child,children/ ox, oxen

9. Some nouns are always plural (things that come in pairs)

9.1. clothes/binoculars/jeans/trousers/people/pajamas/shorts/glasses/scissors

10. plural