Average Pet Mouse Size & Information

pet mouse 4

Unlike their cousins, the gerbil and the rat, mice are very small. On average, they can grow up to 7 inches in length by the time they are adults.

However, each species of mice has its own size. But they are generally a small animal that is very flexible and can easily squeeze through tight openings. 

The average size of a mouse

The average mouse is tiny. If you measure the average mouse from snout from its nose all the way to the top of its tail, they would only measure 7 inches in length, and 3 of those inches would be their tail. 

You would think that because they are so small, they would also be slow to react and run. But you would be wrong. Mice are speedy and are always on the lookout for predators. They can quickly spring into action at a second’s notice and even when they are sleeping. Their tiny claws are sharp, and they’re able to flex all of their nails. So they can climb up trees, homes, wooden bars, and many other types of surfaces to escape their enemies. 

Their small bodies make it simple for them to pull themselves up with their two front legs when dangling from a branch or a ledge.

tiny mouse

Different species of mice and their size

Although the average mouse is 7 inches in length, once you factor in the different species of mice and their various sizes, you will see that there are hundreds of species of mice.

  The Best Foods to Give Your Pet Mice

1. Eurasian harvest mouse

If you live in Europe or tropical parts of Asia, you might come across this mouse quite often. They like to hang out around farmland, where there are a lot of crops. It is one of the smallest mice in existence, and it only grows up to 2.5 inches in length when they are adults. They’re not much heavier either as they only are 1/4 of an ounce in weight.

2. Western Harvest Mouse

This mouse loves to live along the coastline and can be found mostly in the Western United States. It has a dark brown coat all over, and its body is quite round. It usually grows to less than 3 inches in length, and it weighs only half an ounce.

3. House mouse

This mouse is the most common type of mouse there is in the United States. Unlike its other mice cousins, the house mouse is quite fat and has enormous ears. On average, it grows less than 4 inches in length when it is an adult. However, it can weight a full ounce. You can find this mouse in every part of the United States.

4. Deer Mouse

This cute little brown mouse is brown on top and white on the bottom. While its body grows to 4 inches in length when it’s an adult, its tail can grow up to five inches! The deer mouse is found in forests and wooded areas. They can also be found around old wooden structures.

5. White foot mouse

This tiny mouse is usually found in the United States around the southern belt. But can also live in Arizona and Colorado. The white-footed mouse is quite small, especially since the desert is so vast. When they are adults, they only grow up to 4 inches.

  Can Baby Mice Survive Without Their Moms?

6. The silky pocket mouse

Once you see the silky pocket mouse, you will have no doubt why it got its cute name. It is quite small, and his fur is unbelievably soft. It lives in Central and Northern Mexico and around the Mexican border in the United States. It only grows about 2 and 1/2 inches in length, and the males have long tails.

7. The Algerian Mouse

Located along the coast of West Africa and Spain, the Algerian Mouse is a small but rugged rodent with deep dark fur. The Algerian Mouse is known as an old-world mouse, and it usually reaches to about 5 inches in length.

8. The Desert Doormouse

A native of Kazakhstan near Russia, this fat little mouse is light brown and has a sharp pointed face. You can usually grow up to 4 inches in length, but its tail grows to 3 inches. The fur on its underbelly is white.

What affects the size of a mouse?

The essential factor in determining the size, health, and strength of a mouse is its diet. Mice need plenty of vitamins and minerals along with protein to live their active lifestyle. Mice that are kept as pets grow more massive than their wild counterparts and live at least one year longer. The lack of natural predators and the constant abundance of vitamin-fortified food is the reason for a pet mouse’s health and strength. Pellets should for should be the foundation of any Mouse’s diet. Pellets contain vitamins, minerals, antioxidants, a small amount of fat, and fiber that every mouse needs. After pellets, fruits and vegetables are the next levels of the foundation of their diet. Vegetables are fibrous and also full of vitamins, while fruits contain vitamins and tasty sugar that mice love. Protein will be the next since most mice are omnivores. They can eat small pieces of cooked meat. A popular protein-rich food to give your mice is cut up pieces of boiled egg. You don’t need to include salt on the egg. The mice will eat both the white part and the steamed yolk just fine. 

  Can Pet Mice Climb?

Foods that are detrimental to your mouse’s health are human junk foods, an overabundance of fruit in their diet, raw meat, and low-quality pellets full of preservatives and additives.


  • On average, mice grow up to 7 inches long. This measurement includes both their body and their tail
  • There are around a hundred species of mice in the world, and each has its own average growth rate and weight
  • Mice are categorized into two groups: old world mice and new world mice.
  • The mouse’s diet and the amount of food available in its area is the critical factor in developing a healthy size and weight when they are adults.
Was this article helpful?