When Do Puppies Stop Growing?

6 min read
6 min read

Updated - Mar 31st, 2023

Key Points:

  • Puppies can stop growing anywhere from six to 24 months of age.
  • Breed size has a considerable impact on puppy growth. Smaller dogs reach maturity faster than larger dogs.
  • A healthy diet, exercise, and upkeep of preventative care can all help your puppy’s growth.

New puppies are little balls of energy that bring joy and fun to your family. However, they can grow incredibly fast, causing their needs to change in the blink of an eye. As you try to keep up with their physical development and emerging behaviors, you might be wondering, “When do puppies stop growing?” 

Here, we’ll give you an overview of what to expect as your puppy grows. By understanding each phase of development, you’ll be able to better support your pup as they discover themself and the world around them.

When do dogs stop growing? 

Puppies grow the most during their first eight weeks of life. Afterward, their growth rate slows but dogs can continue to develop until they’re about six to 24 months of age.

Typically, a puppy stops growing when they reach full maturity. This means your dog’s growth plates stop producing new tissue and become completely calcified, or closed. This means that they’ve stopped growing and the bone has reached full adult size.

A puppy’s growth timeline varies based on a number of factors, however, including breed, size, sex, genetics, and more.

Puppy growth development

Learning how a puppy develops can help you get a better understanding of your own dog’s growth process. Beginning from birth, new puppies go through the following growth stages:

  • Neonatal period (0-2 weeks): This is the period right after a puppy is born. They are fully dependent on their mothers to survive and have very limited senses. 
  • Transitional period (2-4 weeks): Puppies begin to open their eyes, grow their teeth, and continue to develop their senses. They interact with other puppies in their litter.
  • Socialization period (3-12 weeks): The puppy socialization period begins as the dogs become more aware of their surroundings and start building relationships with people. They start playing, using all of their senses, and testing basic skills. It’s during this period (usually 8 to 10 weeks) that the new pups come home to their families.
  • Juvenile/testing period (3-6 months): At the juvenile or testing period, dogs explore their world with more curiosity. They exhibit various behaviors like puppy biting and teething as they test their boundaries and explore their fears.
  • Adolescence (+6 months): At adolescence, your puppy becomes the equivalent of a teenager and begins to experience puberty. It is highly recommended that pet owners train their puppies and reinforce healthy socialization skills at this stage of growth. It’s also during this time that you might look into spaying or neutering.

Although puppies may continue to develop until 24 months, the American Animal Hospital Association (AAHA) says that some pups can be considered “adult dogs” at six to nine months old.

Factors that affect puppy growth 

These factors can all impact how fast your puppy grows:

Breed size

One of the biggest factors that impacts your puppy’s growth is your dog’s breed, and therefore, size.

Generally, small dog breeds reach maturity faster than larger dog breeds, as larger dogs often need more time to grow and develop their bones.

Toy breeds (Less than 15 pounds)

Because toy-sized dog breeds are the smallest, they mature the fastest. They typically reach their adult size at around six to eight months, and reach physical and sexual maturity by their first year. Some common toy dog breeds include the Toy Poodle, Chihuahua, and the Russian Toy Terrier.

Small breeds (16-25 pounds)

It can take about eight to 12 months before a small dog is done growing. Some examples of small dog breeds are the Boston Terrier, Dachshund and French Bulldog.

Medium breeds (26-55 pounds)

Similar to small breeds, medium breeds can also take eight to 12 months to finish growing. Border Collies, Pembroke Welsh Corgis and Australian Shepherds are all considered medium-sized dogs: 

Large breeds (55-100 pounds)

Large breeds take roughly 10 to 16 months to reach their full size. Some large dogs may take a longer time depending on size, but their dog food may play a significant role in shortening or lengthening their puppyhood. Some large breed dogs include the German Shepherd, Labrador Retriever, and American Staffordshire Terrier.

Giant breeds (More than 100 pounds)

Due to their enormous size, giant dog breeds can take the longest to reach full maturity. It can take 10 to 18 months for them to finish growing, with some even taking 20 months. Giant breeds have different dietary requirements than smaller breeds. Pet owners should make more frequent visits to the vet to ensure that their nutritional needs are being met. 

The Mastiff, Great Dane, and Saint Bernard are all popular examples of giant dog breeds.


Although you can’t say that a purebred dog grows faster or slower than a mixed-breed dog, it is easier to determine the projected growth of a purebred dog because you know their history.

If you know the breed of your dog’s parents, you (or your veterinarian) may be able to make an educated guess, but it is more difficult to evaluate.


Similar to humans, the average female dog is smaller than the average male dog. Some research studies also suggest that female dogs reach maturity faster than their male counterparts, but this hasn’t been confirmed for all breed types.


A poor diet can be detrimental to a growing dog. It’s important to find a high-quality, nutrient-rich puppy food in order to keep your dog growing at a normal rate.

When feeding larger breeds, however, pet parents may actually need to make sure they’re not growing too quickly. Excessive calcium in a large breed puppy’s diet can negatively affect their bone development.

When purchasing dog food, you should check that it’s formulated for your dog’s breed and size so that they receive the nutrition they need. You also should be careful not to overfeed your dog, so that they are able to grow and maintain a healthy adult weight.


Another factor that can affect puppy growth is a disease like intestinal worms, which are parasites that live in the digestive system. Luckily, these worms are easily treatable with prescribed medication. Some thyroid and heart conditions can also stunt your puppy’s growth, but these are rare.

In order to avoid these types of health issues, it’s important to talk to your veterinarian about preventative care and their recommended puppy vaccine schedule.

The bottom line on puppy growth…

Puppies each develop at their own pace, but typically they stop growing at anywhere from six to 24 months. By understanding more about how your pup develops, you’re setting yourself up for success to support them throughout the process. Did you know that Pumpkin Pet Insurance plans help pay 90% cashback on eligible vet bills, so you can help give your pup the best care possible? Consider fetching a quote to protect your puppy’s health as they grow.

Shi-won Oh

Shi-won Oh

Shi-won is a copywriter and an enthusiastic dog aunt to Maltese and Shih Tzu puppies.
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