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When are Puppies Considered Full Grown?

My Rottie Kaiser at 14 months old


It is quite unfortunate that puppy hood is really a very brief season in a dog's life. It may feel like it was yesterday when you picked up your puppy from the breeder and watched her romp around your home unfolding one laugh after another. At one time or another therefore, you may have been asking yourself when will your puppy be full grown. The answer to this question is that puppies grow at different rates depending on their breed, size and their genetic makeup. 

Generally, most dogs reach their full size potential when they are around 12 to 18 months. Small breeds tend to mature much faster than large and giant dog breeds. Generally, toy and small breeds of dogs are considered adult between nine to 12 months of age, while larger breeds may take a bit longer and generally reach adulthood when they are closer to 18-24 months. At this point most dogs will have already reached sexual maturity and their growth plates have closed.

Growth plates are soft areas found around the edge of dog's growing bone that generally close in dogs around 8  to18 months old depending on the breed. When growth plates close they become mineralized bring  the bone growth process to a halt. This is a good time to start conditioning exercises (with the vet's approval) since there are  generally no longer concerns for injuries to the growth plates.

Signs Your Dog May Be Full Grow

Once a puppy has turned to adult there will be both physical and mental signs that confirm the puppy has reached maturity. It is important to understand that a puppy does not transition from puppy to adult suddenly. Rather, there is an inter-mediate period often referred to as ''dpog adolescence''. Following are some signs suggesting your puppy is no longer a puppy.


Once your puppy is adult he will have reached most of his adult size. He will already look like an adult dog. The time were the puppy appeared to be disproportionate because of some bones growing faster than others are over. Your puppy should look like harmonious and should appear as a full sized specimen of his breed.


Your puppy should also have reached about 90% or more of his weight potential. Of course, there are variables here depending on his breed, level of exercise and amount of food fed.


Once mature, dogs should have all their permanent teeth in place. Dogs should have all their 42 teeth in their mouth once they are 12 months old. This often translates into a lower need to chew.

~Sexual Maturity

By now your dog should have already reached sexual maturity. Most female dogs should have gone into heat for the first time around six months in smaller breeds and around one year to one year in larger breeds. At this stage, males will be producing testosterone and will be capable of mating.

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~More Bladder Control

Once mature, dogs will be able to hold their urine for up to eight hours. The dog should be perfectly house trained by this point and will know how to alert the owner when it is time to go.


Most dogs when full grown will be less likely to engage in puppy behavior such as chewing and destroying your yard. They also by now should have learned their place in their rank and there will be less testing behaviors. However, some dogs may still retain a playful and curious behavior throughout adulthood. A full grown dog is not necessarily a mature dog.

What to Expect

Now that your puppy has transitioned into adulthood, you must be aware of some new and different needs. Following are some things to keep into consideration in order to ensure your adult dog meets all his needs.


Once one year old, it is time for your adult dog to get his yearly vaccination boosters. By law, your dog should be getting his Rabies vaccine and depending on your area he may be eligible for a Rabies vaccine worth three years. You should continue giving the Distemper core vaccine and other vaccines depending on your area.


Most dogs should have been spayed and neutered by now and if not, they should be. Large dog breeds are often spayed and neutered around 12-18 months because they may still require hormones to finish up growth. Consult with your veterinarian for recommendations.


At this point, around one year old, your dog may be transitioned to adult food, however larger breeds may still benefit from a few months on large puppy food because they are still in the process of growing.

As seen, the time a puppy becomes full grown is variable. Generally, it is good practice to look up your dog's breed standards and see if your dog has met the typical weight range for his breed along with other important considerations such as shoulder height, muzzle length and so forth. Only this way you can really determine if your dog has reach its breed's full potential.

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