- Not a substitute for professional veterinary help.
Puppies grow up so fast. One day they’re falling asleep in your lap, and the next day they’re too big to fit! So when is a dog no longer a puppy? In general, puppies become adult dogs between one and two years of age. Other markers of a puppy becoming an adult include:
- Sexually maturity
- Physically full grown
- Emotionally maturity
- Responsive to training
- Other dogs view and respond to them as a fellow adult dog
But how can you tell when your puppy is an adult? To help answer the question, we reached out to veterinarian Jennifer Sperry, DVM and veterinary advisor to Pets Plus Us Pet Insurance, for guidance.
When Is a Puppy Considered Fully Mature?
| Breed | Average adult weight | Typical age at maturity |
| Extra-small (Chihuahua, Pomeranian) | Less than 8 pounds | 9-11 months |
| Small (Pug, Dachshund) | 8-24 pounds | 12 months |
| Medium (Australian Shepherd, Bulldog) | 25-49 pounds | 12 months |
| Large (Golden Retriever, German Shepherd) | 50-129 pounds | 18-24 months |
| Giant (Great Dane, Mastiff) | Over 130 pounds | 24 months |
Dogs attain different phases of maturity at different times but are considered adults once they’ve hit all three phases of maturity:
- Sexual maturity, which usually happens first, begins when a dog is around 6 to 8 months old. This refers to female dogs going into heat and male dogs marking territory.
- Physical maturity, which represents a dog’s maximum height and length, is typically reached around 12 months. A dog might seem to grow bigger, but that’s typically muscle mass, not bone growth.
- Social and behavioral maturity take the longest, occurring around 24 months. Social maturity refers to a dog’s ability to handle interactions with their environment, other dogs, and stress.
Some puppies become dogs as early as one year old, and some dogs take up to two years to fully mature.
Signs of Physical Maturity
A puppy can be physically mature before they’re fully adult. In fact, if you’ve raised a puppy, you’ve probably experienced the frustration of having a physically mature pet that doesn’t quite know how to control their body. “The zoomies” are a whole new experience when your puppy weighs 50 pounds.
Physical maturity in dogs looks like:
- Coat changes
- Height and width shifts
- Puberty
- Diet shifts
- Full set of adult teeth
In general, you should start switching to adult-formula dog food when your puppy stops getting taller. The precise “when” depends on your dog’s size. If you’re not sure what your dog’s full size will be—or how close they are to it—reach out to your vet, who can help you determine the best diet for their age and stage.
Emotional and Mental Maturity In Puppies
Emotional maturity coincides with your puppy’s hormonal surges evening out. As puppies grow and become sexually mature, they may act out, test boundaries, and “get in trouble.” But somewhere between one and two years, your puppy will settle down, and their adult personality will emerge.
Watch them for these signs of emotional maturity:
- Listens and responds appropriately to training
- Settles down more readily
- “Listens” and responds to social cues from other dogs
Your puppy’s experiences, or socialization opportunities, can hasten or delay their social maturity.
“The number and quality of social and environmental experiences can affect how a dog matures socially,” says Dr. Sperry. “For example, dogs with minimal opportunities to interact with other dogs may not develop the social skills to engage successfully with fellow canines later in life.”
ROMAOSLO via iStock
Dealing With Immaturity In Puppies: What to Expect
On their way to adulthood, puppies go through different developmental stages. If you’re wondering how much longer you’re going to be dealing with puppy behavior—and what’s next—the following guidelines can help.
Stage 1: 0-2 weeks
Newborn puppies are entirely dependent on their mothers and have only taste and touch for senses.
Stage 2: 2-4 weeks
During this stage, puppies’ sight, hearing, and sense of smell are developing. They also begin to move around and interact with their littermates. You may even hear a little bark or see the tiniest of tail wags.
Stage 3: 3-12 weeks
This stage is a crucial period for puppies to socialize. They become more aware of their environments, including noisy objects like vacuums and TVs. Having positive experiences with other dogs and people beyond their littermates and human parents can also help develop their social skills.
Stage 4: 3-6 months
This is the peak teething stage. Many puppies will begin to gnaw and chew on anything they have access to to help relieve teething pain. This period is also a great time to begin house-training, obedience training, and/or crate training and teach your puppy manners as well as what’s acceptable behavior.
Stage 5: 6-18 months
These months are essentially a puppy’s “teen” years. As they go through adolescence, puppies will begin to noticeably achieve physical and sexual maturity. Their puppy breath fades, teething comes to a stop, and most experience a fear period.
Stage 6: 12-24 months
As your dog physically matures, you may also notice some behavioral regression during this period. Puppies that knew how to loose leash walk may start to tug or avoid other dogs. This is because your puppy is still be mentally and emotionally young. During this time, your puppy will need more training consistency, patience, and support.
Chalabala via iStock
Frequently Asked Questions
Is a 2-year-old dog still a puppy?
When a dog is two years old, that’s usually the end of the puppy phase—though they might continue to display some puppy-like behaviors.
“From a social perspective, a two-year-old dog is just exiting the puppy stage, though they may have been socially and sexually mature for some time already,” explains Dr. Sperry.
When does puppy energy go away?
The answer largely depends on a puppy’s breed and personality, Dr. Sperry tells Rover. Some dogs remain energetic as adult dogs, whereas others will see their energy taper when they’re around two to three years old.
“With regular daily exercise (at least 25 minutes, twice daily), most owners will notice that their dogs become less spontaneously active sometime between two and three years of age. However, many dogs are still considered high-energy, either due to their breed or their individual nature, well through adulthood,” she adds.
Working and herding breeds are especially likely to need plenty of exercise to be good canine citizens, even as adults. Adulthood can, however, make them easier to train, since it typically comes with a better ability to focus.
What is the worst puppy age?
Although “the terrible twos” is a notably trying time for parents of young kids, the first year and a half can be the most challenging time for puppy parents.
Dr. Sperry explains it as a testing of boundaries that happens between about 3 and 18 months of age. Rough play, chewing, roaming, and resource guarding are all characteristic “naughty” puppy behaviors. But there’s more to it than misbehaving. “In reality, dogs are exploring their worlds, and learning the cause-and-effect relationship between their actions and how people, dogs, and the environment respond.”
The solution? Consistent training and regular exercise, plus a healthy dose of patience.
How To Get Help With a Puppy
A dog’s puppyhood is almost always a tough time for a pet parent. Even with its attendant joys, it’s hard, exhausting, and frustrating work. If you’re struggling, you’re not alone—and there’s good help available.
Consider scheduling breaks from your puppy, whether that means hiring a dog walker, enrolling them in doggy daycare a couple days per week, or finding a loving sitter for a few nights away.
A professional trainer can also take the guesswork out of puppy training. And if in-person classes are tough to get to, online classes are a great place to start.
