How are -y endings handled?

A noun ending in a consonant plus y changes y to -ies, so city becomes cities. A noun ending in a vowel plus y just adds s, so day becomes days and boy becomes boys.

When does -f become -ves?

A specific set of nouns ending in -f or -fe change to -ves, such as knife to knives, wolf to wolves, and leaf to leaves. Many others simply add s, like roof to roofs, so the tool uses a known list rather than guessing.

Which words stay the same in the plural?

Some nouns are identical in singular and plural, including sheep, deer, fish, series, and species. The tool recognises these and returns the word unchanged.

How complete is the irregular list?

It covers the most common irregulars across everyday and academic English, including child/children, person/people, foot/feet, analysis/analyses, and datum/data. Rare or domain-specific irregulars may still need a dictionary check.

Does it know which words take -es?

Yes. Nouns ending in a sibilant sound — s, x, z, ch, or sh — take -es, so box becomes boxes and church becomes churches. A short list of -o nouns like potato and hero also take -es.

English Plural Helper

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Forming English plurals is mostly regular but full of small rules and a long tail of irregular forms. This helper applies the standard spelling rules in order and falls back to a curated irregular list, then tells you which rule it used so the result is explainable rather than magic.

How it works

The word is checked against several rules in priority order, stopping at the first match:

1. unchanged set (sheep, fish, series)        -> same word
2. irregular map (child->children, mouse->mice) -> looked-up form
3. consonant + y                               -> drop y, add -ies
4. -f / -fe in the -ves set                    -> -ves
5. ends in s, x, z, ch, sh (sibilant)          -> add -es
6. listed -o nouns (potato, hero)              -> add -es
7. everything else                             -> add -s

Capitalisation of the first letter is preserved, so “Child” becomes “Children”.

Tips and example

Typing “city” returns “cities” via the consonant-plus-y rule; “knife” returns “knives” via the -fe rule; “bus” returns “buses” via the sibilant rule; and “child” returns “children” from the irregular list. English has genuine exceptions the rules cannot all capture — “roof” takes -s not -ves, and some nouns have two accepted plurals (cactuses or cacti) — so for unusual or technical words confirm against a dictionary. The named rule shown with each result makes it easy to spot when a word is following an unexpected pattern.