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Plural of Mouse

The Quick Answer
The plural of mouse is mice.

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.

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.