When Will Your Puppy Stop Growing and Reach Their Full Size?

• Not a substitute for professional veterinary help.

Bringing home a puppy means watching them go through rapid changes. At first, they might seem to have longer legs, bigger paws, and a larger body almost every time you look at them! But as they get older and larger, you might wonder when your dog will stop growing!

For most dogs, growth slows between 6 months and 1 year of age, but growth doesn’t stop all at once. Small breeds may reach their full size by about 9 months, while large and giant breeds can continue growing until the age of 2.

Being “fully grown” isn’t just about hitting a certain weight, explains Dr. Jessica Shepler, lead veterinarian and partner at CityVet Highlands Ranch. It also involves skeletal growth, sexual maturity, and muscle development.

Read on to learn what influences a dog’s growth timeline, how to support them as they develop, and the signs that show they’ve reached their adult size.

Dog Growth Timeline by Breed and Size

According to Dr. Shepler, growth typically begins to slow at different ages depending on breed size:

• Small breeds: 6–9 months
• Medium breeds: 9–12 months
• Large and giant breeds: 12–24 months

Growth tends to taper off gradually. Once the long bones in a dog’s legs have almost fully grown, they’re usually close to their full height. However, they’ll continue to fill out with muscle and weight.

“Most dogs are fully grown by about a year to a year and a half old,” Dr. Shepler says. “At this point, their growth plates are closed and they’ve reached their adult height and weight, though muscle development can continue a bit longer.”

Just keep in mind there’s no exact age when a dog stops growing. Growth rates vary by breed, but they also vary among individual dogs of the same breed.

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Growth chart

Small dogs typically reach their full size faster than larger dogs do, says Dr. Sarah Cortright, veterinarian and medical director at Underdog Community Project. And while purebred dogs usually follow consistent growth patterns, mixed breeds can be less predictable.

While individual growth varies, Dr. Cortright shares this chart showing the approximate percentage of full adult size a puppy typically reaches at different ages.

When do mixed breeds stop growing?

If you have a mixed-breed dog, they might fall into more than one size category, which can make it harder to predict when they’ll stop growing.

As a general rule, most dogs stop growing in height around their first birthday, says Dr. Jamie Whittenburg, veterinarian director at Senior Tail Waggers.

She also suggests looking at their paws and lower leg joints. “Tiny dogs have small, delicate paws and ankles, while giant dogs have large, sturdy paws,” Dr. Whittenburg explains. “Checking your puppy’s feet when they’re about 6 months old can give you a good idea of their eventual adult size.”

How To Tell When Your Puppy Has Stopped Growing

Puppies grow in spurts with rest periods in between.

Dr. Shepler says the following signs help indicate your puppy is reaching full size:

• Teeth: Puppies get all 42 permanent teeth before reaching full height and weight, usually by around the age of 6 months.
• Paw size and proportions: For mixed breeds in particular, paws proportionate to the body usually mean your puppy is fully grown.
• Height and weight: When your puppy’s height and weight stay fairly consistent over time, they’re likely close to their adult size.

If you’d like to check whether your puppy has stopped growing, you can ask your vet for X-rays that show if the growth plates have fully closed. Growth plates are thin regions of cartilage at each end of the long bones in a dog’s legs. These plates are where new bone is added to lengthen the bones.

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Factors That Affect a Dog’s Growth

Genetics, nutrition, environment, and whether a dog is spayed or neutered can all play a part in when they reach full size.

Genetics

A dog’s genes play a significant role in their growth. Puppies with large parents are likely to grow larger, while small breeds usually produce smaller adult dogs. Genetics also sets the baseline for how quickly a dog will grow.

Diet

Nutrition has a direct impact on growth. Puppies need the right amount of calories, protein, vitamins, and minerals to reach their genetic potential, Dr. Whittenburg says.

Malnutrition or calorie restriction can slow growth and may keep a dog from reaching their full size.

Spaying or neutering

Sex hormones help close growth plates in long bones, Dr. Whittenburg explains. Spaying or neutering a puppy removes these hormones, which can allow growth plates to stay open slightly longer.

Puppies spayed or neutered before 8 months of age may grow a bit larger than those altered after their first birthday. If you have questions about the right time to spay or neuter your puppy, your vet can offer more guidance.

Gender

Male dogs generally grow slightly larger and than females, and they may take a bit longer to reach their full growth. These differences are usually minor, but they may stand out more in puppies from the same litter.

Puppy health

Puppies who are frequently sick, injured, or have problems with nutrient absorption may grow more slowly or reach a smaller size than expected. Common concerns include:

• Intestinal parasites: Puppies may experience stunted growth if parasites deprive them of nutrients.
• Liver shunts: If blood bypasses the liver, this can affect the body’s ability to absorb nutrients.
• Growth-related conditions: Issues like panosteitis (“growing pains”) or osteochondritis dissecans (OCD) can temporarily affect growth or mobility, particularly in large breed dogs.

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Care Tips for a Growing Puppy

Growing puppies need careful attention to support healthy development and prevent long-term issues. Here’s what to monitor:

• Body condition score: Ask your vet about monitoring your puppy’s weight and overall body shape. Sudden weight changes or an overweight body can mean they’re eating too much or not getting enough exercise—but keep in mind that puppies are still growing and shouldn’t exercise as much as adult dogs.
• Food intake: Provide a high-quality diet rich in essential nutrients, like protein, fat, and vitamins. It’s also important to make sure your dog gets the right amount of food—puppies need to eat more than adult dogs. Ask your vet about how much to feed your puppy.
• Gait and movement: Pay attention to any limping, stiffness, or unusual movement. These can signal stress on growth plates or other orthopedic concerns that may need veterinary care.
• Body checks: Check your puppy frequently for lumps, bumps, or areas of discomfort. Early detection can help prevent small issues from becoming serious ones.
• Nail care: Trimming your puppy’s nails regularly can help prevent posture issues or discomfort while walking or running.
• Exercise: Puppies need regular movement for healthy muscle development. However, the cartilage on their growth plates is soft and fragile, so too much exercise can lead to injury, so it’s important to stick with puppy-appropriate activities.

Remember, a dog’s physical maturity doesn’t always match their mental or emotional maturity. Even after reaching full size, puppies still need guidance, socialization, and consistent training for lifelong health and well-being.