Whether your puppy just had a litter or you just adopted a new puppy, the one question that always comes to mind is how big is this dog going to be. Smaller breeds are perfect for apartments and inner-city folk because they don’t usually get any bigger than 22 pounds (10 kg).
When does a small dog reach full size? Although most dogs can grow anywhere between 8-24 months, most smaller breeds stop growing between 8-12 months of age. The reason is that the growth plates in their skeletal structure have reached maturity. The remaining growth is going to be width and weight, based primarily on nutrition.
Smaller breeds don’t get bigger than 22 pounds mostly, which makes them perfect for inner-city dwellers, or even just a great kind of dog to have as a companion. Because of their smaller size, these breeds are generally easier to travel with and make excellent lap dogs.
When Does A Small Dog Reach Full Size?
There are many things to consider when looking at the size of the puppy. One of the main considerations is the pedigree of the dog. The pedigree means that the mother and father were both the same breed of canine.

After considering the parents, the next primary consideration is the nutritional requirements that the dog requires to grow successfully. The dietary factors are going to vary depending on the dogs’ breed and size requirements.
Smaller breeds tend to stop growing between 6-18 months, with the most common point resting at around ten months. Since dogs are capable of increasing size up to 24 months, the factors are going to vary based on breed. Smaller breeds reach maturity faster.
While the majority of the growth will be in the first ten months for smaller breeds, they can still grow up to 24 months. In most cases, smaller breeds will reach their maximum growth at or around ten months.
When Does A Small Dog Stop Growing?
A good rule of thumb is 18 months; after 18 months, 99% of dogs are at the size they will remain at for the remainder of their lives. Smaller dogs tend to reach this same maturity between ten and fifteen months. Toy breeds are going to grow at a different rate; their growth period is typically only eight months.
A dog can grow up to 24 months in total, and their skeletal growth is what determines their height as a fully grown dog. After the growth plates reach maturity in your puppy, then the increase is similar to adult humans, and the dog only builds muscle and fat.
However, with every rule, there is an exception, and smaller breeds are that exception. The American Kennel club states that most smaller dog breeds will stop growing at about eight to ten months of age.
Size Class | Age | Common Breed sizes |
Xtra-Small | 6-10 Months | 7-12 pounds |
Small | 8-12 Months | 10-22 pounds |
Medium | 10-18 Months | 20-45 pounds |
Large | 12-18 months | 40-70 pounds |
X-Large | 12-24 months | 120+ pounds |
As you can see, it is not an exact science as to when your pup will stop growing, but more of an estimate based on several different factors.
Can you tell me How Big A Puppy Will Get?
A dog’s paws is a definite give away for how big they will get. According to Trupanion, a puppy must grow into their paws. Most puppies will have bigger paws than they should, and it will look funny at first. Trupanion states that this is a dead giveaway of the size the puppy will grow to be.
Small dog breeds are considered small-sized dog breeds because of their size relative to other dog breeds. Small dog breeds are either under 22lb or 16 inches in height. The Americal Kennel Club has a nifty chart where you can find your dogs breed, and it will tell you how big the dog will get.

Depending on the breed that you have, will depend on how big or small they are. It is a common misconception that the toy breed is a size reference.
Toy breeds are small dogs unless it is a toy breed of a little dog, then it is an extra small breed. The toy group is not a size reference as much as it is a group of smaller dogs placed in a competitive category. One common trait to be placed in this category is their size relative to the size of the standard breed.
At What Age is A Small Dog Full Grown
Most small dogs will reach maturity before bigger dogs at about ten months to one year. Medium-sized dogs can grow to two years old, i.e., beagle, toy Chihuahua, or other small to medium breeds. The canine species as a whole is very similar to other mammals.
The bones inside of your pup are what will continue to grow in height and girth until your puppy is fully developed. After your dog reaches maturity, the growth cartilage in their bones has fully calcified and created a solid bone.
When the growth plate finally hardens and stops adding cells to it, then your pup is at its final height. Smaller breeds reach this final stage faster than larger breeds simply because the mass that must be covered in smaller breeds is lower in comparison to the whole biological system.
In simple terms, the protein molecules and other vitamins don’t have to travel as far or add as much mass to an area by genetic code.
Their weight will be an average based on other breeds of common traits. For instance, most Labradors weigh upwards of 70+ pounds. So if you have a Labrador that is a pure breed, chances are they will be 70-90 pounds depending on birth weight, and nutrition.
Pure bred versus mixed
It is going to be easier to tell how big a pure bred puppy is going to become based on the traits of the parents and the rest of the litter. It is safe to say that if the male is 22 pounds and the female is 23 pounds, then the pup will most likely reach a final weight of 22.5 pounds, and generally, the height will be about the same as the parents.
When you have a mixed breed puppy, it can be more challenging to determine the size that they are going to be. If you are missing information about the mother or father of the puppy, you can only speculate as to how big or small the puppy will remain.
Pure breed Puppies share a list of common Traits such as:
- AKC certification
- Jawline
- Height
- Head shape
- Forequarters
- Hindquarters
- Coat
- Color
- Temperament
- Gait
These Breed Standards are what make the class or group of dog breeds in that class for that specific breed. The standard by which the breed is held to generally describes the breeds’ most common traits, including the size to which they grow typically.
The Takeaway
Smaller breeds can make excellent companions–they are easier to take care of and generally shed less than larger dogs of similar coats. Although it’s good to know how big a puppy will become, it’s a sure bet that the love he or she will show, will be larger than their size.
