When Do Dogs Stop Growing?

You may be questioning when your puppy will stop growing and reach its adult size and character.

Apart from out of curiosity, it is essential to know whether your pup is still growing or has reached its adult size because growing puppies have specific exercise and dietary needs. Plus, you can then go ahead and buy dog beds, harnesses, collars, crates, and other things for your fully-grown pet.

Generally, smaller breeds reach their adult size faster than larger and giant breeds. You can expect a pup from a small breed to stop growing at 6 to 8 months of age. Larger dogs may continue growing to up to 12 to 18 months of age. There are some cases when a puppy can continue growing up to 24 months of age.

There are some factors that can affect the growth of the puppy, including its breed, genes, sex, its diet, and whether it has been neutered or spayed.

Read on for a detailed answer to the question, “when do puppies stop growing?”

When Will My Puppy Stop Growing?

Officially, a dog is considered an adult as soon as it reaches the age of one. But many dogs continue to grow for months and even for up to a year after that.

Larger dogs need more time to grow their larger bones, joints, and skeletons than small ones.

Once the so-called growth plates are completely transformed into fully calcified long bones of the pup’s legs, then it has truly reached its adult size and will stop growing.

Then again, your furbaby will continue growing muscle and fat way after the bones have been formed.

Genetics, Breed, Sex, And Other Growth Factors

If you have a purebred dog and have seen its parents, then it is pretty easy to figure out how big it will become and when it has reached its adult size.

Overall, you can expect a toy or small dog to grow to its full size much faster than a pup from a large or giant breed. The smaller dogs often reach sexual maturity faster than the larger ones too.

According to the AKC guidelines, purebred dogs will most likely stop growing and reach maturity as follows:

  • Small breeds (of up to 22 lbs.) – for 8-12 months
  • Medium breeds (from 22 to 50 lbs.) – for 8-12 months
  • Large breeds (from 50-100 lbs.) – for 10-16 months
  • Giant breeds (100 to 200 lbs. and more) – for 12-18 months

Other Factors Which Can Affect Your Pup’s Growth

Apart from the dog’s breed and sex, there are other factors that can affect its rate of growth, and its adult size, including:


While genetics can influence your dog’s growth rate and final size, there are cases when random variations cause deviations in the growth factor too.

Overall, you can expect your pup to grow to a size approximately the same as its parents. But in many cases, this may not be the case.

Diet And Nutrition

Puppies that suffer from malnutrition or eat a poor diet will not grow as fast and as big and healthy as a dog that eats a complete and balanced diet suitable for its age and breed.

This is why it is essential to feed your puppy the best food suitable for its specific breed and age if you want it to reach its optimal size, strength, and health.

Dog food for puppies contains more protein than the food for adult dogs and includes other ingredients and essential nutrients needed for healthy growth.

This is especially important for large and giant breeds to ensure that their bones and skeletons develop properly and prevent future health issues and orthopedic problems.

The foods made for puppies from giant and large breeds are specially formulated to slow down the growth to a healthy rate because if the pup grows too rapidly, it can develop problems with the bones and joints.

Time Of Neutering And Spaying

Dogs that have been spayed or neutered at a very early age may grow longer growth plates than they should have. This means that it can grow longer legs which can lead to joint issues and mobility problems later on.

The AKC recommends that canines are spayed or neutered after they have reached puberty or are fully grown.


Certain parasite infections, such as roundworms or hookworms, can stunt the growth of young puppies. The reason is that the parasites will steal from the nutrients and calories that the dog needs to continue growing. Once the parasites have been removed, puppies can return to their normal and expected growth rate.

When Do Small Breed Puppies Stop Growing?

The smaller breeds grow much faster than, the larger ones. You can expect a toy or small breed puppy to reach its adult size at the age of 6-8 months.

Medium breeds will reach maturity and their full size by the age of 12 months.

When Do Large Breed Puppies Stop Growing?

As mentioned earlier, large and giant breed puppies take quite a lot longer to reach their adult size. You can expect your puppy from one of these big or giant breeds to continue to grow up to 12 to 18 months. Very large dogs can continue growing up to the age of 24 months.

When Do Purebred Puppies Stop Growing?

The breeder should be able to tell you the approximate size and growth rate of the puppy based on the lineage and experience with previous dogs of the same family.

Predictability is something that many dog parents find the most attractive in purebred dogs. This means you know what size, color, coat type, and temperament you can expect when buying a purebred pup.

When Do Mixed Breed Pups Stop Growing?

The answer to this question is rather tricky, especially if you don’t know anything about the puppy’s parents.

Your veterinarian may be able to determine and recognize certain traits which can help give a prediction about the expected size of your mixed-breed puppy.

You can also feel the sides of the puppy’s ribs for any knobs, which are indicators that the growth plates of the ribs are still growing.

Unlike the common belief, the size of the puppy’s paws or ears is not a reliable indicator of the future adult size of your puppy.

What About The Dogs Who Remain Adult-Sized Puppies?

This phenomenon is pretty common, especially among large dogs. They will reach their full mature size and yet will retain their puppy-like character and demeanor well past 24 months.

There is no scientific explanation for this phenomenon, but it can be pretty fun having a goofy and playful large dog. Still, you may have some explaining to do if your large dog acts like a small boisterous puppy among other people and pups.

The Best Diet For A Growing Puppy

In the USA, there are nutritional guidelines for developing dog food for all life stages the Association Feed Control Officials. The benefit of this dog food for dogs of all ages is that you won’t have to worry about transitioning from puppy food to adult food and then from adult food to senior dog food.

If you prefer, you can choose a dog food that is specifically formulated for puppies of a particular breed size. Your puppy should eat this type of puppy food until the age of about 11 to 14 months, after which you need to transition gradually to the suitable dog food for adult dogs.

In any case, you should follow the guidelines for the quantities of food and the calories you feed your puppy to prevent obesity, which can lead to serious future mobility and other problems such as hip dysplasia.

The best rule of thumb is to keep the puppy lean rather than have a chubby pup later on.

Feeding Giant Breed Puppies

There are special dog foods for pups of large and giant breeds, which are designed to keep the growth rate under control and prevent a very speedy growth which can be detrimental to the development of an animal’s bones and joints.

These foods contain less calcium than other puppy dog foods and are labeled for large-sized dogs expected to become 70 lbs. or more when they reach adulthood.

What Is The Safest Way To Exercise A Growing Puppy?

Puppies are bursting with energy, and it is perfectly normal and healthy for them to be active and want to play. But keep in mind that excessive exercise, like prolonged running and jogging, can lead to problems with the development of the pup’s joints and bones.

This is why, if you want your dog to be your running or jogging buddy, it is advisable to wait for it to grow up to 14-18 months, especially if it is a large or giant breed, before taking it with you for your daily run.

The safest way to walk and play with a growing puppy is on softer ground, such as sand or grass. Outdoor activity should be limited to short distances of up to a quarter of a mile per walk.

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