When Is A Dog Fully Grown?



Watching your dog grow up can be an emotional experience. And at some point, pet parents often will find themselves wondering where all the time went while looking back on the puppy years with nostalgia. All of this is part of the joy that comes with the experience of being a pet owner and one of the most rewarding aspects of raising a dog.


Sometimes though, if you are raising a breed for the first time or are a new dog owner in general, you might wonder how you will even be able to tell when they are fully grown! Below we will help provide you with some clarity and methods to determine if it's time to fall into nostalgia for days passed. Read on if you want to learn more about how to tell when a dog is fully grown!



When Is A Dog Fully Grown 

In truth, there is not one single way to determine when a dog will be fully grown. Many factors contribute to determining when your dog is fully grown, such as their adult size and genetics, along with nutrition. Much of determining when a dog is fully grown is left up to educated guesswork. Dogs of different breeds and genetic lines will look very different from one another when fully grown. It is a good option for some to reference a breed-specific puppy weight chart to get a rough idea of when your dog will be fully grown.


Despite these specifics, you will, of course, notice your dog gradually losing its puppy-like characteristics in favor of those common in adult dogs. This may consist of your dog losing its baby teeth or swapping its soft puppy fur for a thicker adult coat. These are some hints that your dog might provide to show their age, but there are other more precise ways to tell.



two dogs meeting face to face



When Do Dogs Stop Growing?

The age at which your dog will stop growing depends on the general size of your dog's breed. Most small dogs will have a rapid growth period earlier in their lives, while large dogs will take longer to get to their full size. This alone makes it hard to generalize when dogs stop growing, making it necessary to reference information particular to your dog's specific breed. Aside from breed-specific factors, other things will contribute to puppies growing at different rates.



Factors That Determine When Your Dog Stops Growing

Most of what will determine when your dog will stop growing lies in its breed. However, their physical growth is not set in stone and is determined by things other than just their breed. When a dog stops growing is partially determined by the overall size that your dog is expected to grow to in the first place.


Toy breeds will stop growing at a very young age after going through a series of quick growth spurts, but large breeds will have a longer growing period spanning over many months. The general rule is that the larger the breed, the longer it'll take until they reach their adult size.



Average Ages When Dogs Reach Adult Size

Although there are many more specific things at play when determining when a dog will reach its adult size, we can estimate the approximate age where growth will stop based on the size expected from that dog breed.


Small Breed Dogs

Small dog breeds have a quick and drastic period of growth early in their lives as a puppy. It usually takes about 8-12 months for most small dog breeds to reach their adult size. Once at this adult size, most small dogs will fall somewhere between 12 and 25 pounds.


Some popular small dog breeds include:


  • Chihuahua
  • Pomeranian
  • Pug
  • French Bulldog





Medium Breed Dogs

Medium dog breeds will have a slightly more spread-out growth period, reaching 12-15 months maturity. It is dependent on breed, but a medium-sized dog is likely to fall somewhere between 25-50 pounds. Some common medium dog breeds are:


  • Corgi
  • Cocker Spaniel
  • Border Collie
  • American Foxhound
  • Australian Cattle dog


Large Breed Dogs

Large dog breeds usually take a bit longer to grow than medium dogs. Most large dogs will reach maturity in 12-18 months. Once full-sized, they will likely be somewhere between 50-100 pounds.


Some favorite large dog breeds include:


  • German Shepherd
  • Beauceron
  • Belgian Sheepdog
  • Borzoi


Giant Breed Dogs

Naturally, giant dog breeds have the longest period of growth, resulting in their massive size! These incredible creatures reach maturity in a similar amount of time to large dogs, 12-18 months. Giant dog breeds can be expected to grow over 100 pounds in weight!


Some of the most iconic giant dog breeds are:


  • English Mastiff
  • Leonberger
  • Cane Corso
  • Bernese Mountain Dog



How Do Puppies Grow, Anyway?

In a sense, puppies grow in a way not too different from how we do! Growth doesn't happen all at once but comes from a part of the bones in your puppy's legs called growth plates. These plates start as a layer of soft cartilage, and as they expand to their full size, they close and harden into bone.


Afterward, your dog will see no additional bone mass as they age. However, just like humans, they will continue to develop fat and muscle after reaching physical maturity.



Other Factors that Alter Puppy Growth Rate

A puppy's size depends on more varied factors than just the breed that they come from. Looking at their breed as a whole is a good starting point, but puppy size will vary depending on other factors.


Genetic Differences

Even though a breed carries specific genetics that will strongly affect its size, your dog's parents will pass down some of their genetic traits to your puppy. Meaning if your puppy's parents were larger, it's a possibility the adult size of your dog could be similar but not a guarantee.  



Finding high-quality puppy food and treats goes a long way when regulating and encouraging a dog's growth; provide them with too little of either, and you might find your puppy's growth stunted! To make sure you give your puppy all the healthy nutrients they need, make sure to provide them with good puppy food to encourage proper nutrition from an early age.



How Does Spaying or Neutering Affect Puppy Growth Rate?

Many dog owners wonder if spaying or neutering their puppy will affect their growth rate or overall adult size. Growth hormones will, of course, play a role in how your puppy grows. For the most part, however, research shows that spaying or neutering your puppy would likely only result in the difference of a few millimeters.


Because this difference is so minimal, this should not be used as a primary reason to put off spaying or neutering your puppy. Even so, other minor differences can be experienced as the result of sterilizing your dog, but these differences remain minor. As a result, these differences will likely not be noticeable to most owners.


If you need any further information regarding spaying or neutering, we recommend getting veterinary advice from your puppy's doctor.


Related: How Much Does It Cost to Neuter a Dog



The Adult-Sized Puppy Phenomenon

Puppy growth includes more factors than just the physical growth of your pet. A growing dog also goes through the process of reaching emotional maturity. However, not all dogs reach emotional maturity at the same age.


Even after a year or two of growth, you might feel that your dog maintained its puppy-like demeanor. Their face may still be soft and rounded, possessing those wide puppy-like eyes so essential to their overbearing cuteness. They might still prance around and show the same excited behavior one might expect from a young puppy.


While it is not fully clear why some dogs exhibit these characteristics, they could be related to social factors the puppy learned earlier in their development. Like people, most puppies grow at different rates and will reach maturity with time and experience. Give them the time and structure to grow healthily, and you'll be sure to be the proud owner of a wonderful companion.





At What Age Is A Dog Fully Grown?

The age that a dog reaches its full growth varies heavily on the breed size. Because there are so many different dog breeds, there is no one size fits all rule in determining the proper age for a dog to be fully grown. However, there are some developments a puppy will go through during growth which constitute getting to a mature state.


These characteristics will not fully determine whether or not your dog is finished growing but can help you recognize that they are moving through some of the steps. These developments are consistent across breeds and include:


  • Sexual Maturity - A dog's reproductive organs develop at around six months of age, showing that your dog has become sexually mature. At this point, it is recommended to schedule some vet visits to spay and neuter your puppy.
  • Emotional Maturity - Puppies display a lack of attention by constantly becoming distracted, needing playtime, and generally acting like a baby! As your puppy grows, it will gradually become more relaxed and responsive to training.
  • Physical Maturity - Puppies will grow at a different rate, but most will likely reach full physical growth within two years. This includes closing the growth plates, a more developed musculature, and often the sharpening of certain facial features.



family with their dog on the road



How Much Will A Dog Grow After 6 Months?

Most breeds tend to grow at different rates, but the first half-year of their lives can provide us with information to determine how much more growing they have to take care of. Toy and small breeds tend to reach their full size after the first six months, so expect your Chihuahua or Pug to pretty much be fully grown by this time. Medium and large dogs will likely have reached approximately one-third of their total size by this time, and giant breeds will take the longest, often only growing to about half their total size by the six-month mark.





Final Thought

Seeing your puppy grow up, and helping them along the way, can be one of the most rewarding aspects that come with being a dog owner. You'll go through so many different moments with your dog, watching them grow from a delicate baby to an excitable and curious puppy, all the way to a responsible and stable companion. Your dog is a unique individual who will follow your path in life, but they'll be as glad to have you as their owner as you are to have them as your pet. Find more dog care posts here.


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