Plural

+ -s

a cat – cats

a dog – dogs

1) -s, – ss, -x, -sh, -ch, -z + -es

a bus – buses

a class – classes

a box – boxes

a dish – dishes

a watch – watches

a buzz – buzzes

2) -o + -es/-s

a tomato – tomatoes

a potato – potatoes

a hero – heroes

a volcano – volcanoes

But: a photo – photos

a kilo – kilos

a piano – pianos

a radio – radios

3) a consonant + y -> i + -es

a baby – babies

a party – parties

But: a vowel + y + -s

a boy – boys, a day – days

4) -f/-fe -> v + -es

a shelf – shelves

a knife – knives

a wife – wives

(+ a calf, an elf, a half, a knife, a thief, a leaf, a life, a loaf, a wolf)

But:

a roof – roofs

a safe – safes

(+ belief, cliff, cuff, grief, gulf, proof)

Exceptions

man – men

woman – women

person – people

child – children

foot – feet

tooth – teeth

ox – oxen

goose – geese

mouse – mice

deer – deer

fish – fish