Plural of Mouse

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The Plural of Mouse

The plural of mouse is mice.

• Domestic mice sold as pets often differ substantially in size from the common house mouse.
• Mice and rats have the same organs in the same places, with the difference of size.

Certain plurals do not add a letter to the end, but instead change the word itself. The noun mouse is an example of this. There is no ruling for these types of plurals. You have to learn them.

Be aware that the plural of computer mouse can be computer mice or computer mouses, but computer mice is far more popular.
See this graph for yourself using Google's Ngram viewer, which scans millions of published articles and books.

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The Standard Rules for Forming the Plurals

The table below shows the standard rules for forming the plurals of nouns in English.

Type	Example of Type	Forming the Plural	Plural
Most Nouns	cat scythe	add s	cats scythes
Noun Ending s, sh, ch, x or z	bus dress	add es	buses dresses
Nouns ending [consonant] o	mango zero tomato	add either s or es (There are no rules for this - you have to know.)	mangoes or mangos zeros tomatoes
Nouns ending [vowel] o	patio ratio	add s	patios ratios
Nouns ending [consonant] y	story penny	change the y to an i and add es	stories pennies
Nouns ending [vowel] y	storey () donkey	add s	storeys donkeys
Nouns ending f or fe	dwarf knife	ves and/or s (There are no rules - you have to know.)	dwarfs knives
Exceptions	mouse louse	some nouns undergo a vowel or letters change	mice lice
More exceptions	salmon sheep	some nouns do not change at all	salmon sheep

Read more about English spelling rules.

Why Is There Confusion over the Plural of Mouse?

There is confusion because some nouns become different words when they're made plural (usually due to a letter change). There are no easy ways to remember these plurals. They have to be memorized.

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