Singular and Plural Nouns: Rules with Examples and Exceptions
A singular noun names one person, animal, place or thing (one book, one city). A plural noun names more than one (two books, ten cities). Most English nouns form the plural by adding -s, but some add -es, change -y to -ies, change -f to -ves, or change shape completely (child → children).
This lesson gives every spelling rule for plural nouns with examples, a quick-reference table, the irregular and "no-change" plurals, and the nouns that are always singular or always plural.
To make a regular noun plural, add -s to the singular: book → books, pen → pens, girl → girls. The spelling rules below cover nouns that need something different.
Singular and Plural Rules at a Glance
| Noun ends in | Rule | Examples |
|---|---|---|
| most nouns | add -s | book → books, pen → pens, girl → girls |
| -s, -ss, -x, -z, -ch, -sh | add -es | bus → buses, class → classes, box → boxes, watch → watches, dish → dishes |
| consonant + y | change y to -ies | baby → babies, city → cities, story → stories |
| vowel + y | add -s | boy → boys, day → days, key → keys |
| -f or -fe (many nouns) | change to -ves | leaf → leaves, knife → knives, wolf → wolves |
| -f or -fe (some nouns) | add -s | roof → roofs, chief → chiefs, cliff → cliffs |
| consonant + o (some nouns) | add -es | potato → potatoes, tomato → tomatoes, hero → heroes |
| -o (other nouns) | add -s | photo → photos, piano → pianos, radio → radios |
| irregular nouns | change the word | man → men, child → children, foot → feet |
| some nouns | no change | sheep → sheep, deer → deer |
Rule 1: Add -s to Most Nouns
✅ one pen → two pens
✅ one teacher → many teachers
✅ one river → three rivers
Rule 2: Add -es After s, ss, x, z, ch, sh
These endings make a hissing sound, so we add -es to give an extra syllable that is easy to say.
✅ bus → buses, gas → gases
✅ class → classes, glass → glasses
✅ box → boxes, tax → taxes
✅ church → churches, watch → watches, bench → benches
✅ dish → dishes, brush → brushes
Nouns ending in a single z usually double it: quiz → quizzes. And when ch sounds like /k/, add only -s: stomach → stomachs, monarch → monarchs.
Rule 3: Nouns Ending in -y
Consonant + y: change y to -ies
✅ baby → babies
✅ city → cities
✅ story → stories
✅ country → countries
✅ lady → ladies
Vowel + y: just add -s
✅ boy → boys
✅ day → days
✅ key → keys
✅ monkey → monkeys
❌ monkies
Names of people keep the y: the two Marys, the Kennedys.
Rule 4: Nouns Ending in -f or -fe
Many nouns change f / fe to v and add -es (so the plural ends in -ves).
✅ leaf → leaves
✅ knife → knives
✅ wife → wives
✅ life → lives
✅ shelf → shelves
✅ thief → thieves
✅ wolf → wolves
✅ half → halves
✅ calf → calves
✅ loaf → loaves
Other nouns simply add -s. There is no rule to tell them apart, so learn them as a list:
✅ roof → roofs
✅ chief → chiefs
✅ belief → beliefs
✅ cliff → cliffs
✅ proof → proofs
✅ safe → safes
A few nouns take either form: scarf → scarfs or scarves, dwarf → dwarfs or dwarves.
Rule 5: Nouns Ending in -o
This is the least regular rule. Some nouns ending in consonant + o take -es and others take -s.
✅ potato → potatoes
✅ tomato → tomatoes
✅ hero → heroes
✅ mango → mangoes (mangos is also used)
✅ echo → echoes
✅ volcano → volcanoes (volcanos is also correct)
✅ photo → photos
✅ piano → pianos
✅ video → videos
✅ kilo → kilos
✅ memo → memos
Nouns ending in vowel + o always add -s: radio → radios, zoo → zoos, kangaroo → kangaroos, studio → studios.
Rule 6: Irregular Plurals
Some very common nouns do not follow any spelling rule. Their plural is a different word or has a changed vowel. You must learn them by heart.
| Singular | Plural | Singular | Plural |
|---|---|---|---|
| man | men | mouse | mice |
| woman | women | louse | lice |
| child | children | goose | geese |
| foot | feet | ox | oxen |
| tooth | teeth | person | people |
Person becomes people in everyday English. Persons is used mainly in legal or formal notices ("persons under 18"). Also remember that woman is pronounced /ˈwʊmən/ and women /ˈwɪmɪn/.
Practise these with the Irregular Plurals worksheet. Words from Latin and Greek, such as crisis → crises and phenomenon → phenomena, are covered in Foreign and Classical Irregular Plurals.
Rule 7: Nouns with the Same Singular and Plural
A few nouns have the same form in the singular and the plural. Use the verb or a number to see which is meant.
✅ one sheep → ten sheep
✅ one deer → a herd of deer
✅ one fish → many fish (fishes is used for different kinds of fish)
✅ one series → two series
✅ one species → many species
✅ one aircraft → five aircraft
Rule 8: Compound Nouns
In most compound nouns, make the last word plural: bus stop → bus stops, toothbrush → toothbrushes, schoolbag → schoolbags. In a compound with a hyphen and a preposition or phrase, make the main noun plural:
✅ mother-in-law → mothers-in-law
✅ passer-by → passers-by
✅ commander-in-chief → commanders-in-chief
More in Compound Nouns and Noun Adjuncts.
Nouns That Are Always Plural or Always Singular
Always plural
Some nouns name things made of two parts and are used only in the plural. We count them with a pair of.
✅ My trousers are too long. / I need a pair of trousers.
✅ These scissors are sharp.
✅ Where are my spectacles?
✅ Other examples: jeans, shorts, pyjamas, clothes, thanks, congratulations, belongings
Always singular (no plural)
Uncountable nouns have no plural form and take a singular verb. Do not add -s to them.
✅ Please give me some information. ❌ informations
✅ She gave me good advice. ❌ advices
✅ The furniture is new. ❌ furnitures
✅ Other examples: luggage, news, homework, equipment
Read more in Nouns Always Plural or Singular, Countable and Uncountable Nouns and the worksheet on them.
Singular and Plural in Other Words
Nouns are not the only words with singular and plural forms. A plural noun needs a plural verb, pronoun and determiner.
| Singular | Plural |
|---|---|
| this book | these books |
| that child | those children |
| He is a teacher. | They are teachers. |
| The student has finished. | The students have finished. |
| It was a good idea. | They were good ideas. |
For the full set of verb rules, see Subject-Verb Agreement.
Other Cases: Numbers, Letters and Words
- Years and numbers: add -s with no apostrophe: the 1990s, two 5s.
- Abbreviations: CDs, PINs, MPs.
- Dozen and hundred stay singular after a number: two dozen eggs, three hundred rupees.
- Letters: an apostrophe makes them clear: mind your p’s and q’s.
Common Mistakes
| ❌ Incorrect | ✅ Correct |
|---|---|
| childrens | children |
| mans, womans | men, women |
| monkies, keies | monkeys, keys |
| informations, furnitures | information, furniture |
| a scissor / this trouser | a pair of scissors / these trousers |
| two sheeps | two sheep |
✍️ Quick Practice — Write the Plural
- church
- city
- day
- knife
- tomato
- child
- sheep
- roof
- photo
- brother-in-law
Answers: 1. churches | 2. cities | 3. days | 4. knives | 5. tomatoes | 6. children | 7. sheep | 8. roofs | 9. photos | 10. brothers-in-law
✍️ Quick Practice — Correct the Error
- The childrens are in the playground.
- She gave me many advices.
- Two womans were waiting outside.
- These scissor is blunt.
- I bought three loafs of bread.
Answers: 1. The children are in the playground. | 2. She gave me a lot of advice. (or: some advice) | 3. Two women were waiting outside. | 4. These scissors are blunt. | 5. I bought three loaves of bread.
For more, print the Singular and Plural worksheet or take the nouns practice test. See also Types of Nouns.
Summary
- A singular noun names one; a plural noun names more than one.
- Most nouns add -s. Nouns ending in s, ss, x, z, ch, sh add -es.
- Consonant + y becomes -ies; vowel + y just adds -s.
- Many nouns in -f or -fe change to -ves, but some (roof, chief, cliff) add -s.
- Nouns in -o vary: potatoes, heroes, but photos, pianos.
- Irregular plurals (men, women, children, feet, teeth, mice) must be learned; some nouns do not change (sheep, deer, species).
- Some nouns are always plural (scissors, trousers) and others have no plural (information, advice, furniture).