When Do Dogs Stop Growing
When Do Dogs Stop Growing
Watching your puppy grow is one of the joys of being a dog owner. They change so quickly in those first few months that it’s only natural to wonder when it will all level out. The truth is, there isn’t one simple answer. The point at which a dog stops growing depends on several factors, including breed, size, and genetics. Most dogs reach their full height by around a year old, but some will continue to fill out and mature well into their second year.
While physical size is the most obvious marker, growth also includes muscle development, bone density, and emotional maturity. So even if your dog has reached their adult height, there may still be more development to come under the surface.
Growth Timeline by Size
Size plays a big role in how quickly dogs reach their full potential. Smaller breeds tend to mature faster and may reach their full size by the time they are eight to twelve months old. Medium breeds take a bit longer, often finishing their growth by fifteen months. Larger breeds grow more slowly, usually reaching their full height and weight between twelve and eighteen months. Giant breeds, such as Great Danes and Mastiffs, can continue to grow until they are nearly two years old.
This difference is mainly due to how long the growth plates stay open. These are areas of softer bone tissue near the ends of long bones, and they remain active longer in larger dogs. Once these plates close, your dog’s bones have stopped growing.
How to Tell if Your Dog Has Stopped Growing
There are a few clear signs that your dog has finished growing. One of the most noticeable is when their weight and height remain consistent over several months. You might also see their body fill out, especially around the chest and shoulders, giving them a more adult look. As they mature, their energy levels may begin to even out, and they start to behave more like an adult dog rather than a boisterous puppy.
If you’re unsure, your vet can give you a better idea. In some cases, they may suggest an x-ray to check if your dog’s growth plates have closed completely.
Why Knowing the Growth Timeline Matters
Understanding when your dog will stop growing can help you make informed decisions about their care. Puppies need a specific type of food that supports rapid development. Switching to adult food too early can affect bone and muscle growth. Likewise, young dogs shouldn’t be over-exercised, especially larger breeds. Too much running or jumping while the bones are still developing can lead to joint issues later on.
The timing of neutering or spaying can also be influenced by growth. In large breeds, some vets may advise waiting until the dog is fully grown before going ahead with the procedure, to support healthier joint development.
The Role of Neutering in Growth
There is evidence that neutering a dog before their growth plates close may slightly affect their size. Some dogs neutered early may grow a little taller than they would have otherwise because the hormones involved in sexual maturity also signal the body to stop growing. However, the difference is usually minor and should be weighed alongside other health and behavioural considerations.
Discussing the timing of neutering with your vet is the best way to find the right approach for your individual dog, especially if they are from a large or giant breed.
When Dogs Reach Mental Maturity
Just because a dog has stopped growing physically doesn’t mean they’re finished developing emotionally. Many dogs, particularly those from working or larger breeds, take longer to mature mentally. It’s common for dogs to still behave like puppies well into their second or even third year. During this time, consistency in training, structure, and social experiences play a major role in shaping long-term behaviour.
Smaller breeds tend to settle into adult behaviours more quickly, but every dog is different. Patience and clear routines help guide them through the final stages of maturity.
Growth Isn’t Always Linear
Puppy growth often happens in spurts. One month they’re lanky, the next they’ve bulked out. It’s not a smooth curve, and many owners worry when their pup suddenly looks too skinny or too stocky. This is normal. Just like with human teens, dogs grow in uneven stages—height might come before weight or vice versa.
If you’re ever unsure whether your dog is growing at a healthy rate, a vet can assess their body condition and offer reassurance or suggest changes to diet and exercise.
Genetics and Lineage Matter
Even within the same breed, dogs can grow at different speeds. Genetics play a huge role. Dogs from working lines may mature more slowly than those from show lines, for example. If you know your dog’s parents, that can often give you a rough idea of how big they’ll get and when they'll stop growing.
Nutrition Can Influence Growth
Diet won’t make your dog bigger than their genetics allow, but overfeeding a puppy, especially large breeds, can lead to joint and bone issues. It’s important to feed a balanced, age-appropriate diet. Large breed puppy food has controlled calcium and phosphorus levels to support slower, healthier growth and reduce the risk of conditions like hip dysplasia.
On the flip side, underfeeding or giving poor-quality food can result in stunted growth or developmental issues.
Vets Use Growth Charts
Just like baby growth charts for humans, vets sometimes use puppy growth charts to track weight over time. These can help identify if a dog is growing too fast or too slowly. This is especially useful for large or giant breeds where rapid growth can lead to long-term issues.
Teeth Can Indicate Development Stages
While not a perfect growth marker, your dog’s teething timeline often aligns with key developmental phases. By six to seven months, most dogs have their full set of adult teeth. This usually means they’re entering adolescence and nearing the end of their most dramatic growth phase. Teething discomfort, chewing, and behavioural shifts often accompany this period.
Mental vs. Physical Maturity Can Be Confusing
A lot of owners think their dog has “settled down” once they stop growing physically—but then the teenage phase kicks in. Between 6 to 18 months, many dogs go through a second wave of testing boundaries, ignoring recall, or acting more independent. So while the body might be done growing, the brain still needs guidance.
That’s why consistent training and structure through adolescence is so important. It’s not a sign of regression—it’s normal development.
Summary
Most dogs reach their adult size between eight months and two years, with smaller breeds growing faster and larger breeds taking more time. While physical growth might end in the first year or so, your dog’s full development continues beyond that, including muscle tone and behaviour. Knowing what to expect helps you support your dog with the right nutrition, exercise, and care during these key stages. Whether your dog is a tiny terrier or a towering Great Dane, understanding their growth journey helps them grow into a happy, healthy adult.