Find the plural form of any English noun instantly. Covers irregular plurals (children, mice, phenomena), Latin forms (cacti, fungi), and standard rules with examples.
| Rule | Pattern | Example |
|---|---|---|
| Standard | Most nouns | cat → cats, dog → dogs |
| -s, -x, -z, -ch, -sh | Add -es | box → boxes, watch → watches, buzz → buzzes |
| Consonant + y | Change y to -ies | city → cities, baby → babies |
| -f or -fe | Change to -ves | knife → knives, leaf → leaves, wolf → wolves |
| -o | Add -es | potato → potatoes, hero → heroes, tomato → tomatoes |
| -us (Latin) | Change to -i | cactus → cacti, fungus → fungi, nucleus → nuclei |
| -is (Greek) | Change to -es | analysis → analyses, crisis → crises, thesis → theses |
| -on | Change to -a | phenomenon → phenomena, criterion → criteria |
| -um | Change to -a | datum → data, curriculum → curricula |
| -a | Add -e | larva → larvae, alga → algae |
| Irregular | Memorized forms | child → children, man → men, mouse → mice |
English pluralization follows a set of predictable rules, but the language also preserves many irregular forms from its rich history. The standard rule is simple: add -s to most nouns. However, pronunciation and spelling considerations create several important exceptions.
Nouns ending in sibilant sounds (-s, -x, -z, -ch, -sh) require -es to make pronunciation easier. Words like box, watch, and buzz would be difficult to pronounce with just -s, so English adds a syllable: boxes, watches, buzzes.
Words borrowed from Latin and Greek often retain their original plural forms. This explains why cactus becomes cacti, analysis becomes analyses, and phenomenon becomes phenomena. These patterns are worth learning because they apply to many scientific and academic terms.
Some of the most common irregular plurals come from Old English, where vowel changes signaled plural forms. Man/men, woman/women, tooth/teeth, and foot/feet all follow this ancient pattern. While there is no formula to predict these, they are among the most frequently used words in English.