When is a Shih Tzu Full Grown?

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Shih Tzus are so cute and tiny. When you adopt one as a puppy, it might be hard to tell when they will stop growing. When is a Shih Tzu fully grown?

A Shih Tzu is considered fully grown at ten months. At this point, the Shih Tzu will reach its maximum size and weight. They can be anywhere from 9 to 10.5 inches tall and weigh between 6 and 16 pounds. Because Shih Tzus are in the toy group, they tend to mature more quickly than other dog breeds.

In this article, we will determine when a Shih Tzu is considered to be fully grown. We will talk about what they will look and act like when they are fully grown. We will also discuss the phases of development that they will go through before they are fully grown. Finally, we will help you figure out how much your Shih Tzu will weigh when they become fully grown from an early age.

I have owned and loved dogs for my entire life. I learned a lot about dogs and how to take care of them through my own experienced, but I also conduct a lot of research. I have learned a lot about different breeds of dogs and how they age and mature. I hope that you can learn something from this article about how Shih Tzus grow up.

In this article

‍When is a Shih Tzu Full Grown?

Shih Tzus are outgoing, affectionate, and playful. They are one of the most well-known dog breeds in the toy group. Being in the toy group of dog breeds simply means that the dog is very small on average. Shih Tzus are known as being lapdogs. Shih Tzus make excellent pets, especially for anyone living in a small apartment in a city. They can easily join you on walks or as a companion in your bag.

Dog breeds in the toy group, because they are so small, are known for maturing quickly. Because of this, Shih Tzus are usually fully grown by the time that they are ten months old. Shih Tzus grow and develop a lot in the first few weeks and months of their life, and then reach their fully grown size before they are a year old.

When a Shih Tzu is fully grown, it can weigh anywhere from six to sixteen pounds. You can estimate how much your Shih Tzu will weigh when it is fully grown at about eight weeks, though we will talk about that more later.

Even though they are fully grown at about ten months, Shih Tzus can still have some of their crazy puppy personality until they are about a year old. After they turn one, they usually calm down some. However, even fully mature Shih Tzus are still outgoing and energetic.

What Stages of Development Do Shih Tzus Go Through?

Shih Tzus go through many phases of development in a short ten month period. Before they reach adulthood, Shih Tzus go through five distinct phases of development. We will discuss these phases in the next few sections.


Like most dog breeds, when Shih Tzus are born, they cannot see or hear. They are born with their eyes and ears closed, and it takes about ten days before their eyes to open at all. Once they are open, their vision is usually blurry for another two weeks. At about three weeks old, the puppy will have clear vision and its ears will start to open. Once these senses are activated, the puppy moves on to the next phase of its development.

Three to Six Weeks Old

Now that the puppy has their vision and hearing at about three weeks old, they can begin to explore their surroundings. During this short three week phase, the puppy will grow a considerable amount. That means that while the puppy is exploring and playing a lot, they are also taking a lot of naps and having frequent downtime.

It is during this phase of development that the puppies will begin to recognize each other, their mother, and their human owners. At six weeks old, Shih Tzu puppies can begin to be weaned from their mother, though generally the longer they stay with their mother, the better,

Six to Eight Weeks Old

During this short two week period, your Shih Tzu puppy will have much more energy than ever before and they will become extremely adventurous. The puppy will want to explore anything that they can access. They will also learn to get around obstacles to explore your home, yet they are too young to be potty trained quite yet. Be ready to pick up messes anywhere that your Shih Tzy puppy might be. During this phase, the Shih Tzu puppy will start to grow fuzzy hair that is distinctive of the breed.

Two to Eight Months Old

When your Shih Tzu puppy turns about two months old, they will start to teethe, meaning they will start destroying items around your home if left unattended. Your puppy is still learning about their surroundings. They just grew these new teeth, and they don’t necessarily know that chewing on shoes or furniture is wrong.

Try not to get mad at your Shih Tzu puppy when they partake in these behaviors. Instead, try to implement some training. It is at this point in their development that training will be effective for them. Start with redirecting chewing behaviors toward toys instead of your possessions. Then, you can move on to basic commands, house training, and walking on a leash.

While your puppy did a considerable amount of growth in the first few weeks of their life, they will continue to grow a lot during this period. This phase consists of six months where your puppy is learning and growing continually.

Eight to Twelve Months Old

This is the final stage of development into adulthood and beyond for your Shih Tzu puppy. During this period, their growth will slow down and they will lose some of their puppy-like behaviors, such as chewing on everything in sight. They will start to retain even more of their training. During this phase, as long as you keep up with training, you will have fewer and fewer accidents until your dog is completely potty trained.

Keep in mind that during the first ten months of their life, your puppy is growing a lot. Your vet will likely recommend that you feed your puppy special puppy food that is high in calories to help keep up with their growth. Once your puppy reaches adulthood at ten months old, you will need to cut back on their food and transition them to an adult diet.

When your puppy is just a few weeks old, you can estimate their appropriate adult weight. You can use this estimation to determine how much food your adult Shih Tzu needs each day. Make sure, as you are figuring this out, that you are monitoring their weight and checking in with the vet to make sure you are not over or underfeeding them.

How Do You Estimate The Size Of A Healthy Adult Shih Tzu?

We have mentioned a few times throughout this article that there is an easy way to estimate a healthy adult weight of your Shih Tzu when they are just a few weeks old. This information can help you figure out how big your puppy will be when they are fully grown. It will also help you determine how much kibble you need to feed them when they are a puppy and an adult.

To estimate their adult weight, you will need to weigh your Shih-Tzu puppy at eight weeks old. At this point, they should be exclusively breastfed by their mother. Their mother will produce an appropriate amount of milk to keep her puppies growing at the correct rate. At around eight weeks, you will weigh the puppy as they are being weaned from their mother.

You can find something called a “growth” chart online or from your vet. This chart will tell you the healthy weight of your puppy when they grow up based on their weight at eight weeks old.