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 mature
- 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.
How Long Is a Dog Considered a Puppy?
Dogs attain different phases of adult maturity at different times. Some puppies become dogs as early as one year old, and some dogs take up to two years to fully mature.
Dr Sperry explains that dogs hit different milestones toward adulthood at various times.
Sexual maturity usually happens first, when a dog is around six to eight months old.
Skeletal maturity—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.
And social and behavioural maturity take the longest, occurring around 24 months.
How long is a dog a puppy physically?
A puppy can be physically mature before they’re fully adult. Physical maturity is when your puppy reaches their adult height, which depends on breed. In general, small breeds are fully grown around 12 months of age, while larger breeds can take between one to two years to finish growing. Giant breeds almost always take two full years.
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 20 kg.
| Breed | Average adult weight | Typical age at maturity |
| Extra-small (Chihuahua, Pomeranian) | Less than 4 kg (8 pounds) | 9-11 months |
| Small (Pug, Dachshund) | 4-11 kg (8-24 pounds) | 12 months |
| Medium (Australian Shepherd, Bulldog) | 11-22 kg (25-49 pounds) | 12 months |
| Large (Golden Retriever, German Shepherd) | 23-59 kg (50-129 pounds) | 18-24 months |
| Giant (Great Dane, Mastiff) | Over 59 kg (130 pounds) | 24 months |
How long is a dog a puppy mentally?
Mental or emotional maturity, on the other hand, is when a dog acts like a dog instead of a puppy. As with every other aspect of puppy development, the process of becoming mentally or emotionally mature takes place over time. You may not see it happening, but one day you’ll realise that your puppy has become a dog.
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.
Puppies mature at their own rate, so it’s hard to identify the specific moment a puppy becomes an adult. As your puppy grows, 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
According to Dr Sperry, social maturity depends biological development as well as social and environmental experiences.
“The number and quality of social and environmental experiences can affect how a dog matures socially. 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,” she says.
That means your puppy’s experience can hasten—or delay—their social maturity.
ROMAOSLO via iStock
How long is a dog considered a puppy for food?
Diet is one way to distinguish between the puppy and adult years. Puppy food has more calories than adult dog food because growing pups need more energy to fuel their day. As your puppy stops growing, you will eventually switch to dog food for adult dogs.
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:
- small breeds: nine to 12 months
- medium breeds: around 12 months
- large breeds: 12 to 16 months
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.
At What Age Is a Dog No Longer a Puppy?
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 behaviour—and what’s next—the following guidelines can help.
Stage one: up to two weeks
Newborn puppies are entirely dependent on their mothers and have only taste and touch for senses.
Stage two: two to four 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 tail wag.
Stage three: three to 12 weeks
This stage is a crucial period for puppies to socialise. 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 four: three to six 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 behaviour.
Stage five: six to 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, although emotional and behavioural maturity may still be months away.
What will maturity look like?
Puppies are considered adults once they’ve reached physical, sexual, and emotional maturity.
- Physically, dogs should have reached their full height and have all of their adult teeth, and their behaviour should become calmer and more predictable.
- Signs of sexual maturity include going into heat for females or marking their territory for males.
- Lastly, emotional maturity can encompass a wide range of traits, but one sign to watch for is a dog’s ability to handle interactions with their environment and other dogs with more confidence and less stress.
Chalabala via iStock
Frequently Asked Questions
Is a two-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 behaviours.
“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 three and 18 months of age. Rough play, chewing, roaming, and resource guarding are all characteristic ‘naughty’ puppy behaviours. 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.
