Plural Nouns

Add -s: most nouns just add -s — cat → cats, book → books.

Add -es: nouns ending in s, x, z, ch or sh add -es instead — box → boxes, watch → watches, bus → buses. Some nouns ending in -o add -es too (potato → potatoes), but many just add -s (photo → photos).

y → ies: nouns ending in a consonant + y change the y to i and add -es — baby → babies, city → cities.

Irregular plurals don't follow the -s pattern at all — they change form completely and have to be memorized: man → men, woman → women, child → children, person → people, foot → feet, tooth → teeth, goose → geese, mouse → mice, louse → lice, ox → oxen, die → dice.

Latin and Greek plurals keep their original endings, mostly in academic and scientific English: cactus → cacti, fungus → fungi, nucleus → nuclei, radius → radii, criterion → criteria, phenomenon → phenomena, analysis → analyses, crisis → crises, thesis → theses, hypothesis → hypotheses, bacterium → bacteria, curriculum → curricula, medium → media, appendix → appendices, index → indices.

Several of these also have a regular -s/-es plural in everyday English: cactuses, formulas, indexes (in books), appendixes (in the body). The full searchable list is in the reference table below.

-f / -fe → -ves: leaf → leaves, knife → knives, life → lives, wife → wives, wolf → wolves, half → halves, shelf → shelves, thief → thieves, loaf → loaves, calf → calves.

Many -f nouns just add -s: roof → roofs, chief → chiefs, belief → beliefs, cliff → cliffs, chef → chefs, proof → proofs. A few accept both: scarf → scarves or scarfs, hoof → hooves or hoofs.

-o → -oes: potato → potatoes, tomato → tomatoes, hero → heroes, echo → echoes. -o → -os: photo → photos, piano → pianos, radio → radios, video → videos, zoo → zoos, logo → logos. Nouns with a vowel before the -o (radio, zoo) and shortened words (photo from photograph) take -s. Some accept both: volcanoes or volcanos, mosquitoes or mosquitos, zeros or zeroes.

Some nouns only have a plural form and always take a plural verb: scissors, trousers (US: pants), jeans, shorts, pyjamas (US: pajamas), glasses, binoculars, pliers, clothes, goods, thanks, outskirts, belongings, surroundings, congratulations. My jeans are new, not my jeans is new.

To count the "two-part" ones, use a pair of: a pair of scissors, two pairs of jeans. Police and cattle are also always plural: The police are here.

A few countable nouns don't change at all in the plural: sheep, deer, fish, moose, salmon, trout, cod, bison, aircraft, spacecraft, series, species, means, offspring. One sheep, two sheep. This series is great; both series are great.

Fishes exists, but it is mainly used for different species of fish, especially in scientific writing. In everyday English the plural is fish: I caught three fish.

Uncountable nouns like information, advice, furniture, and luggage have no plural form at all — you can't say informations or advices. To count them, use a unit: a piece of advice, two items of luggage.