One of the very exciting parts of being a puppy owner is getting to watch your dog grow into adulthood. However, while in the midst of the process, all of the changes involved in puppyhood can be very overwhelming.
Additionally, because having to buy new canine accoutrements every time your pooch outgrows their collar can get expensive, you may want to know ahead of time which collar, harness, bed, or other accessories to buy so that they will fit your pup once they become an adult.
Owners who have just adopted a puppy for the first time (or have adopted a breed of puppy new to them) may wonder, “When will my dog stop growing? Just how big will this puppy get when they’re an adult?”
Although the exact timeline differs depending on factors including size and genetics, most dogs are fully grown by the time they are between one and two years old. In addition to other good lifestyle choices, a healthy diet plays a key role in the appropriate growth of dogs.
Let’s look at the factors involved in a dog’s physical development, when full growth is achieved, and whether any characteristics can indicate just how big a puppy will become when fully grown.
How Long Does It Take Most Puppies to Become Fully Grown Adult Dogs?
Although there are differences in growth rates for dogs of different sizes, breeds, and genetic backgrounds (more on that below), by the time most dogs are one to two years old, they are considered to be adults.
The surefire way to know whether or not your dog is done growing is to know when their growth plates have closed, typically revealed by the dog no longer growing in height. However, adulthood is not measured solely in physical size, though that may be the final stage of growth for many dogs.
Dogs experience growth phases that can be likened to human babyhood, adolescence, teenage years, adulthood, and geriatric years. Unlike humans, though, the first three phases are condensed into a very short period of time that can be delineated based on the dog’s sexual, emotional, and physical maturity. Once the dogs are mature in all three areas, they can be considered adults.
While the process may be longer or shorter for dogs of different breeds and sizes, most pups mature along this timeline:
- Newborn – 10 Weeks: After birth, puppies cannot initially see or hear. They gain these senses a bit before they are two weeks old, though, and also begin to effectively use their legs around three weeks old.
At five weeks old, puppies begin to transition to solid foods. Between weeks six and ten, they continue to develop their personalities, grow physically, and explore their world. Puppies also undergo a “fear period” when they are between 8 to 10 weeks old.
- 10 – 16 Weeks: Though this is a perfect time to begin training, puppies from ten to sixteen weeks of age are very rambunctious and high-energy. They continue to grow and, at this phase, also go through teething. Some dogs’ eyes may also change color during this period.
- 4 – 6 Months: Growth continues. As dogs continue to acclimate to their world, training can continue; it should be noted, though, that a dog’s attention span may still be very short and lessons taught will need to continue to be reinforced. Bladder development continues as well, leading to fewer bathroom trips needing to be made throughout the day and night.
- 6 – 12 Months: Depending on their size, breed, and gender, most dogs reach sexual maturity at six to nine months of age. Male dogs may be fertile before six months but not typically before five; additionally, larger dogs tend to undergo sexual maturation later than smaller dogs. Along with sexual maturity, dogs six months to a year old undergo emotional and behavioral changes akin to teenage mood swings.
Growth continues throughout this time period. By about eight months of age, puppies should have replaced all of their puppy teeth with adult teeth. Also, many smaller- and medium-sized dogs complete the rest of their physical growth by the time they are 9 to 12 months old.
Many dogs can be considered fully grown at a year old. Though they may be adults, at this age they are still young adults, and as such, may still need additional training to continue to solidify their good habits. Thankfully, at this point they should be less hyper than they were as puppies, which should make training easier and more likely to stick.
Differences in the Growth Timeline: Size
One of the biggest predictors of your dog’s growth timeline is their size. Though breed can be a useful indicator of a dog’s growth process, some dogs are naturally on the smaller or larger side for their breed, which can make a difference in how quickly they will grow.
Most dogs can be lumped into at least one of the following size categories:
- Giant Breeds, such as the Great Dane, Irish Wolfhound, or Saint Bernard.
- Larger Breeds, such as the Bloodhound, German Shepherd, or Rhodesian Ridgeback.
- Medium Breeds, such as the Australian Shepherd, Labrador Retriever, or Whippet.
- Small Breeds, such as the Beagle, Pembroke Welsh Corgi, or Shetland Sheepdog.
- Toy or Teacup Breeds, such as the Cavalier King Charles Spaniel, Shih Tzu, or Toy Poodle.
In general, small dogs finish growing more quickly than large- or medium-sized dogs. Very small dogs tend to fully mature around eight to ten months of age, while medium and larger breeds may take a year to 15 months for the same maturation. Giant breeds take the longest, usually requiring eighteen to twenty-four months to be fully grown.
Interestingly, despite maturing more quickly, smaller dogs generally tend to live longer than larger dogs (teacup dogs are an exception, though: they may experience more health problems compared to other small dogs).
It should be noted that there may be variations in the growth timeline for breeds considered to be in the same size family—for instance, a smaller Australian Shepherd may grow more quickly than a larger Labrador Retriever, despite both being “medium” dogs—and that some dog breeds may straddle categories depending on their weight.
Differences in the Growth Timeline: Breed
Knowing a dog’s breed and their lineage can help you figure out how quickly they may grow. Although many breeds are scaled by size, dogs that are similar sizes but different breeds may develop at different rates.
Additionally, the speed at which the dog’s parents grew may provide some insight to your particular pooch’s growth timeline. If you got your dog from a breeder, they may be able to provide you with that information. While your dog’s genetics will not be identical to their parents’, knowing when they graduated from puppyhood to adulthood may help you estimate when your dog will be fully grown.
The growth timeline of a mutt may be more difficult to tell compared to a purebred, in part because the dog’s lineage is likely unknown and also because their breed may be unclear. However, if you have any idea what breeds might be mixed in your pooch, you may be able to speculate a bit more accurately.
For instance—as previously mentioned—if it is clear that your pooch is a blend of toy dog breeds, they will very likely finish their growth faster than a mutt with giant dog breed genes.
If it is impossible to tell your dog’s probable breed mix, you may just have to wait and see how they develop. Thankfully, unless your dog is part giant breed, it is likely that they will be completely done growing by or before eighteen months of age.
If you are unsure of your mutt dog’s age, estimating their growth timeline will be even trickier. However, vets can estimate your dog’s age based on their teeth (primarily through color and the presence of any puppy teeth); thus, your vet may be a good resource if your dog’s age and breed are both unknown.
Differences in the Growth Timeline: Health Factors
Certain health problems—especially those that affect dogs’ physical growth—may make figuring out when your dog will become an adult more difficult.
For instance, a dog’s growth may be stunted if they were the runt of the litter. Though many runts end up being a normal size for their breed once they are adult dogs, some do not receive enough nutrition as puppies and end up being smaller than would otherwise be expected for their breed.
Some dogs may also have hereditary growth-related conditions, such as pituitary dwarfism, that can cause unexpected changes to the dog’s growth. In the case of pituitary dwarfism, dogs develop normally for their first few months of life, then their growth slows. Additionally, they may experience other symptoms such as hair loss or signs of hypothyroidism.
Thankfully, through the course of puppy vaccination visits and other checkups growing dogs require, it is likely that your veterinarian would notice a health problem slowing your dog’s growth and would be able to treat it quickly.
Encouraging Healthy Growth: Meeting Dietary Needs
One way to help your dog navigate the process of growth successfully is to feed them an appropriate diet for their age. Healthy feeding includes both feeding puppies the nutrients they require and feeding them on the right schedule.
Growing puppies need to eat more often than adult dogs do, though in smaller quantities. When your dog is about four to six months old (depending on their breed, size, and growth), the vet is likely to suggest switching your pooch from three or more daily meals to two. However, the number of meals you give daily before they reach that point will depend on their nutritional needs.
It is vital that you feed your dog the correct amount of food for a number of reasons. Underfeeding is a problem because it can stunt dogs’ growth, potentially leading to health complications.
Overfeeding puppies is a problem because it can lead to an undesired growth spurt, which in turn may also lead to health problems later in the dog’s life. It is important to keep dogs of all ages at a healthy weight. Overweight and obese dogs—large and small breeds alike—tend to have shorter lifespans, and as such, it is important to establish healthy routines for your dog early in their life.
Finally, it is important to know that the larger number of feedings young puppies require also lead to an increased number of bowel movements compared to adult dogs. As your pup develops bowel control and is transitioned to fewer daily feedings, their bathroom breaks will also decrease.
Encouraging Healthy Growth: Appropriate Veterinary Care
Visiting the vet is important for growing puppies not only so that they can receive their vaccinations on time but also because these appointments serve as opportunities for vets to check on puppies’ growth and overall health.
Because vets are very familiar with the growth cycles of different breeds, they will be able to tell whether something abnormal is going on with your pooch and can provide interventions early, when needed.
It is important that you take your puppy to all of their necessary vet appointments as they are growing, and if you suspect that something might be wrong or if you have a question about changing your dog’s routines (including their diet and exercise), you should reach out to your vet for guidance.
Does a Puppy’s Paw Size Really Indicate How Big Will Become?
Although it’s more of an old wive’s tail than real science, the size of a puppy’s paws can sometimes be a helpful indicator of a dog’s future size. Big dogs generally have disproportionally large paws as puppies, and often do “grow into them.” The same dynamic exists with small dogs — they often have relatively small paws when they are puppies.
But there are plenty of exceptions to this “rule,” and it cannot be depended on to make accurate predictions of a dog’s eventual size. Breed variations complicate matters, as certain breeds have paws that don’t align with the “rule.” For instance, herding dogs like Australian Shepherds have fairly small paws for their size, and Bully breeds such as French Bulldogs have large paws relative to their overall size.
With mixed breeds, the calculation becomes even more difficult. If you don’t know what breeds are in your puppy, the variations mentioned above can make it even harder to estimate your dog’s ultimate size.
While it’s fun to try to anticipate your puppy’s eventual full-grown size, remember that there is no truly accurate way to do this. It’s probably best to enjoy your puppy’s short childhood and be happy with however they turn out. Just don’t invest in an improperly sized crate, etc. with the idea that it will work through their adulthood until you actually know how big the dog has become.
While there are ways you can aid your dog in healthily navigating the growing process, there are many aspects of canine growth that cannot be definitively known but can only be predicted. The journey from puppyhood to adulthood is not indefinite—while owners may miss parts of it when it’s over, most are likely to be glad when their dog is finally a well-adjusted adult.
Knowing your dog’s breed, size, and genetic history may help you estimate the best dog bed for their eventual full-grown body, but even the best plans sometimes do not work out the way you would hope. As much as you can, enjoy watching your pup grow—they will become an adult sooner than you may think!