How Do I Know When My Hamster Is Fully Grown? Let’s Find Out

When I bought my first hamster, I immediately wondered when my cute little pet would grow up.

How do I know when my hamster is fully grown?

Hamsters are fully grown when they are 3 months old or they are very close to their full length. When they are 3 months old, they are fully mature for breeding.

In today’s article, you will learn more about when they are fully grown, whether can they stop growing early, and other issues related to this topic, so let’s get started right away.

How do I know when my hamster is fully grown?

Hamsters grow very fast and in 3 months they will already have reached their maximum size or will be at the end of their growth.

After 3 months, they become fully sexually mature for reproduction, so you should separate them from other hamsters until then.

Since there are different breeds of hamsters you will notice that they do not all grow to the same size.

For example, Syrian hamsters are the most noticeable when they grow up because they are the largest breed and there is a big difference between a baby and a Syrian hamster that is 3 months old.

Dwarf hamsters as the smallest breed are the least noticeable when growing up and they certainly grow and reach their maximum at 3 months of their life.

When are Syrian hamsters fully grown?

Syrian hamsters are the largest of all other hamster breeds and they reach their maximum growth at 3 months of age.

After this period they are already mature enough and can start breeding if you keep male and female Syrian hamsters together in a cage.

Syrian hamsters grow about 5-8 inches, of course, sometimes there are small deviations and they grow more than this size, but this rarely happens.

To know that your Syrian hamster has reached its maximum growth, it is enough to look at its appearance and certain signs that they show.

When Syrians get darker fur it is a sign that they have reached their maximum growth, or the rear ends will become larger and their testicles will be visible.

Female Syrian hamsters, when they are fully grown, will start to smell a little more when the mating time comes, precisely every 4 days, and if there is a male hamster nearby, they will also start to squeak.

On average, Syrian hamsters can live about 2-3 years, although there can always be exceptions and they can live more or less depending on how you have kept them.

A healthy and regular diet can increase their lifespan, but after the second year of life, they start to age and move more slowly.

Old age reduces their ability to be active and they will prefer to rest which is completely normal behavior.

How do I know Roborowski hamsters are fully grown?

Roborovski hamsters reach their full growth at about 3 months. They become mature for breeding at around 4-5 weeks of age,

This breed of hamster grows to about 2 inches or 5 cm in length, and they are one of the smallest breeds of hamster.

If you see the color of their fur you will notice that after 3 months it is completely clear and this is a sign that they have reached their maximum growth.

As for their life span, this breed of hamster lives for about 3-4 years in domestic conditions, while in the wild they live for about 2 years because they don’t have the same living conditions do I know when my hamster is fully grown

When are Campbell’s hamsters at maximum growth?

Campbell hamsters are fully grown at around 3 months of age, just like other hamster breeds.

But they, unlike other breeds, can start breeding a little earlier somewhere around the age of 4 weeks when they are already mature enough.

As for size, they reach about 3-4 inches, with possible slight deviations from this size. Campbell’s hamsters live an average of about two years, although if you raise them well they can live a little longer.

You can visually tell that Campbell’s hamsters are at their maximum size by their white belly and back fur that turns gray-brown and a darker line running down their back.

How do you know when Chinese hamsters are fully grown?

Chinese hamsters are fully grown at around 2-3 months of age. They begin to be ready for breeding at around 9-11 weeks of age.

Chinese hamsters grow to about 3-5 inches in length and are larger than other smaller breeds, but smaller than Syrian hamsters.

An interesting thing about Chinese hamsters is that they have a long tail that can be about an inch long, which makes them look similar to a mouse.

Regarding the lifespan of Chinese hamsters, they live about 2 years in domestic conditions, while in nature they can live even less due to more difficult conditions.

When are winter white hamsters fully grown?

Winter white hamsters are fully grown at around 3 months of age like all other hamster breeds.

They begin to be mature for breeding a little earlier, that is, at the age of about 4-6 weeks. This breed of hamster can grow to about 3-4 inches in length with slight deviations.

They are called winter white hamsters because they change the color of their fur depending on the seasons.

In the summer, the color of their fur becomes darker or dark gray, while in the winter it turns white, which is a very interesting phenomenon.

What factors affect the full growth of hamsters?

There are certain factors that affect the growth of hamsters, of course, the first is their breed, according to which you can know approximately how big your hamster will grow.

Male hamsters are usually larger than female hamsters, although exceptions sometimes occur. It is rare to see when a female hamster is larger than a male of the same breed of hamster.

Genetics affects the maximum growth of hamsters, because if the parents of the baby hamster are small, then their baby will also be small, while if the parents are big, the baby hamster will have a bigger growth.

Does a fully-grown hamster need a bigger cage?

Yes, a fully grown hamster will need a larger cage if it was originally grown in a smaller cage.

Hamsters obviously grow very fast, so if they have a smaller cage at the beginning, then it will be too small for them and you have to buy them a bigger cage.

For example, for an adult Syrian hamster, you need a cage that is 24 x 12 inches and 12 inches high.

It is best to get the same cage for other breeds of hamsters because a larger cage allows more comfort for your pet.

The larger cage can be kept for the future if you keep another hamster, then you will not need to buy a new cage again.

Small cages are not good for hamsters as they cause stress which then leads to diseases and shortens their do I know when my hamster is fully grown

How can I help my hamster grow properly?

To make sure your hamster grows properly and reaches its full size you need to provide it with a healthy and proper diet and exercise.

Hamsters need to eat foods rich in protein and fiber, as well as vegetables and fruits to reach their full growth.

Hamsters also need activities such as exercise on the wheel, climbing ladders, and other objects in order to grow in a normal way.

What are the signs that my hamster is growing normally?

When hamsters grow normally, it can be seen by their constant increase in size and weight.

When they grow properly they increase their activity and exercise levels daily as the days go by.

Hamsters when growing normally in 3 months will reach the maximum growth predicted for their breed with few exceptions.

Can hamsters have stunted growth?

Yes, babies can have stunted growth or stop growing prematurely and not reach their intended size.

This can happen if they are malnourished and do not get enough nutrients, calcium, and protein.

Hamsters can have stunted growth due to a certain disease or due to genetic inherited factors.

Do bigger hamsters eat more than smaller hamsters?

Larger hamsters eat more food than smaller hamsters which is completely normal.

That’s why you need to be careful as your hamster grows and increases their food and water supply.

As they grow very quickly, you would not want your pet to starve so you need to ensure that your hamster has enough food in their cage.

Read more: How To Care For Old Hamster? All You Need To Know


Hamsters grow very fast and they reach their maximum growth in 3 months. All breeds of hamsters are not the same size, Syrians are the largest, while other breeds of hamsters are smaller.

Since hamsters grow very fast, you should be ready to provide them with a large cage and a comfortable life in their short life.

Sometimes genetics play a role and hamsters may be larger or smaller than normal.

Male hamsters almost always grow slightly larger than female hamsters, except in rare cases when the reverse can happen.

Read more: Why Is My Hamster Not Feeding Her Babies? Let’s Discover