About a year ago, A friend of mine got an adorable St. Bernard puppy. The black and white furball was the cutest thing we had ever seen. My friend would carry it everywhere because it was just too cute to put down. Little did she know that soon it would be too big to carry! At 6 months of age, our adorable little puppy was 21 inches tall and 95 pounds heavy, and at that point, we all scrambled to search exactly when do dogs stop growing?!
Rambunctious and adorable, puppies are capable of stealing any heart. They are soft and cuddly, making them a most adorable companion. But just like childhood, puppyhood goes by in a flash. Before you know it, your puppies grow into adult dogs. Here comes the question; when? When does a puppy become a dog?
Some of the experts say there is no definite answer to the question. The general rule of thumb is smaller breeds of dogs reach maturity faster than large ones. The rough estimate is the duration can vary from six months to twenty-four months depending upon the gender, breed, and other genetic factors.
In this guide, we will try to answer the average growth of dogs according to their size, factors that affect dog growth, and more!
Factors that Affect a Dog’s Growth
A dog’s breed is not the only thing that plays a role in the growth and size of a dog. Genetic differences and nutrition are the other two important factors that combine with a genetic predisposition to determine the size and build of a dog.
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Genetics
Like any other species, all dogs do not have a single genetic pattern. The unique genetic code of each dog breed greatly influences its build, weight, height, and duration of growth.
All dogs have a unique genetic code with two types of traits; the traits passed down from their parents and the traits that manifest due to the genetic recombination of dog breeds.
What does this mean?
It means that it is very likely for a puppy with larger parents to take longer to grow eventually into a large size dog. However, it can never be guaranteed. Sometimes small parents give birth to large dogs, and sometimes it happens the other way around.
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Nutrition
Puppies need proper nutrition and care while growing up. A lack of nutrition or proteins can sometimes hinder the growth process resulting in the inability of a dog to grow into a full-size canine.
So, if you want to keep your dog healthy and happy or want your little fluff ball to grow into a big dog, then you should focus on feeding him only high-quality food that is full of nutrition.
Here the question arises what is a high-quality and suitable food for a growing dog?
There are specified food options available in the market which have high amounts of protein and other minerals dogs need while growing. Especially, larger dogs are prone to developing orthopedic problems and deficiencies later in their life if they are not fed well during their growing phase. Hence, it is better if you choose food that is made particularly for large dogs.
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Breed Size
There is no denying that genetics and nutrition have a fair amount of influence on a dog’s growth, but when it comes down to predicting a dog’s size, there is no definite answer. So, the best way to predict is by keeping in mind the genetic history of your canine friend AKA your dog’s breed.
This includes a few things like; if you are trying to predict the growth size of a dog, you should be asking yourself some questions like, is your dog an American Hairless Terrier or a Boston Terrier? Were your dog’s parents big, small or medium if compared against their breed’s standards?
The AKC has published a general guide of dog growth, which you can use to determine when do dogs stop growing. The gist of it is:
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Small Dog Breeds
Small breed dogs generally grow to a maximum of 22 pounds, and the age of reaching maturity is between 8-12 months.
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Medium Dog Breeds
This category encompasses the dog breeds that usually weigh between 22 to 50 pounds, and the process of growth usually stops anywhere between 8-12 months of age.
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Large Dog Breeds
Dog breeds belonging to this range can weigh between 50 to 100 pounds when they grow up and the period of growth usually lasts till the age of 10 -16 months.
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Giant Dog Breeds
These dogs can weigh anywhere from 100 to 200 pounds and sometimes more. They take at least 10 months to reach maturity and as much as 24 months sometimes.
In all these cases, female dogs stop growing before their male counterparts as they are comparatively smaller in size than the males.
These measures are quite accurate and precise when your dog is purebred, but what if you have a pup that is of mixed-breed?
Well, in these cases, the dog’s full growth depends upon its parents. One can calculate the maximum weight and growth rate by taking the average of its parent’s weights.
Let’s just say one of the puppy’s parents weighed 50 pounds, and the other one weighed 70 pounds; then, your pet would most likely grow up to 60 pounds and take anywhere between 10 to 16 months to reach maturity.
You can judge the category your dog’s parents fall into by looking at their weights. This also helps you determine in which size category your dog will fall into.
When Do Mixed Breed Dogs Stop Growing?
If your dog is a mixed-breed dog, you can determine the duration of growth in the following way:
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You Know the Parents or Breed of Your Dog
In this case, even if your puppy is of a mixed breed, you can estimate its size by averaging the weight and size of parents.
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You Don’t Know the Parents or Breed
This is the tricky one when you either don’t know the breed or the parents of your puppy. In this case, here are a few things that can help you with determining the size and weight of your pup:
- Check if there is loose skin: While some dogs like bulldogs have some naturally loose skin, other ones don’t. If your dog has loose skin, it generally means that it will grow for a longer duration.
- Check growth plates by feeling ribs: When you can feel the bones’ edge in the rib cage, that means the growth plates are in the process of hardening. It is not an indication of the adult size, but it shows that your puppy is still growing.
If you are still unsure, you can visit your local veterinarian to determine whether your puppy has stopped growing.
Can A Vet Help You Determine When Do Dogs Stop Growing?
The answer to this question is not a simple yes or no. Contrary to what the internet might tell you, there is no specified formula that a vet can use to determine the maximum size or growth of a puppy.
However, when you visit your vet, they can give you detailed information about your pet’s breed and also about the breeds of parents if they are known. They also look at the physical markers like bone structure, pup’s feet, as well as its weight and overall size, to gauge their expected size, weight, and duration of growth.
With the increase in cross-breeding, the utility of size charts is decreasing, and it has become harder to calculate the age of maturity, size, and weight of any dog. So, if someone claims they can predict the size of your pet with complete certainty, then they are probably wrong.
Can A DNA Test Be of Any Help in Determining When Do Dogs Stop Growing in Height or Size?
You might want to get a DNA test done for your pet to understand its lineage and the size it will grow up to, and its estimated weight as well. However, this path may be a lot trickier than you think. Genetics is not simple; even if you know the breeds of both the parents of a dog, you cannot determine which breed’s trait will dominate in the offspring. So, a DNA test does not tell the size of your pet accurately either.
Can Paws or Ears Indicate the Adult Size of a Puppy?
The simple and plain answer to this common question is NO.
Despite being correlated to the size of a dog, sometimes paws cannot be used to estimate the full growth of a dog. Especially when it comes to puppies, you cannot say anything about their size by looking at their paws as it is very common for puppies to have disproportionately small or large paws as compared to the rest of their body.
In the same way, paws cannot be used to estimate age ears cannot be used either. Again, the best way to determine that is by visiting a vet or knowing the lineage of the dog to get a rough idea.
Do Dogs Stop Growing After the First Heat?
Most of the dogs attain sexual maturity at the age of 6 to 15 months on average and soon after that have their first heat. Although smaller breeds reach their sexual maturity earlier, and sometimes the giant and large breed dogs get their first heat at the age of 18 to 24 months.
Sexual maturity or having the first heat does not stop the growth of dogs. They continue to grow in height and size till the age of twelve to twenty-four months depending upon the breed they belong to.
So, if someone asks when do dogs stop growing in height or size, you cannot tell them that it happens when they get their first heat because it is not accurate.

When Do Puppies Grow the Most?
Puppies keep growing till a certain age, and while different changes happen to their bodies at different stages, there are surely some stages during which they grow the most. Although not all puppies grow the same way and at the same age.
There are always variations, but here are some milestones you should look out for to figure if the growth rate of your furball is normal:
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Neonatal (Birth to 2 weeks)
At this stage, mostly puppies sleep the day away and only wake up to nurse. Within a week, they start weighing almost double their birth weight.
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Transitional (2 weeks to 4 weeks)
Puppies learn to open their eyes and start walking slowly in this phase of transition. They also start showing some teeth growth.
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Juvenile (4 weeks to 12 weeks)
This period comes before sexual maturity and puberty in dogs. At this point, your pup will start running around and playing to develop muscles. If you ask, when do the puppies grow the most? The answer is their Juvenile period is the time when the most growth happens. At this stage, your little pup shows signs of growth every day.
If you notice that your little canine companion is being more furious, aggressive, or fearful than usual during this time, then do not worry because it is quite normal during the juvenile period of growth.
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Adolescence (6 months to 12 months)
At this stage, male dogs become interested in sex, and female dogs start to get their heat as well. At this point, sexual maturity will be predominant and physical growth will slow down. Moreover, your little furball will start losing its baby fur to be replaced by the adult coat.
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Full Maturity (1 year to 2 years)
At this point, your pup would have transitioned into a dog. They will not drastically grow in height at this stage, although over time, muscle growth can still be significant.
Now You Know When Do Dogs Stop Growing
Most of these guidelines are for purebred dogs; the growth for mixed breeds often differs, but it mostly depends on the size and breed of the parents. We tried to answer some major questions people have regarding dog growth.
Now when you know the answer to all these questions, you can make an informed decision while adopting a pup. Let us know if you have any more questions about the growth of dogs.