Plural of Mouse

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The Quick Answer
The plural of mouse is mice.

The plural of computer mouse is computer mice or computer mouses.

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 just have to know.

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

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, so they generally have to be memorized.
Another Interactive Exercise
Here are three randomly selected questions from another exercise on plurals, which can be edited, printed to create an exercise worksheet, or sent via email to friends or students.

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See Also

Unusual pluralsPlural forming table Quirks with forming plurals Forming the plurals of abbreviations Forming the plurals of compound nouns