When Do Puppies Stop Growing?

If you happen to have a young dog at home who’s approaching the one-year mark, you’re probably wondering when your once-pint-sized puppy will reach full size. Though many believe that all dogs stop growing after a year, this isn’t always the case. Dogs grow at different rates according to breed, health, diet, and other factors. However, experts do provide some general guidelines that should help you figure out whether your particular pup has already reached full size or may still have some growing up to do.

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On Breed and Build
Generally, the larger-framed and stockier the dog, the longer it will take for it to become fully grown. Having said that, the smallest dog breeds like Chihuahuas and Yorkshire Terriers are the quickest to reach full size, usually taking between 9 - 12 months to reach their adult size. Smaller but stockier breeds like Shih-Tzus and Pugs take just a bit longer, from between 11 - 13 months. Medium-sized dogs like Cocker Spaniels and Bulldogs take between 12 - 16 months to stop growing, with the stouter Bulldog taking a bit longer to reach full size and weight. Likewise, stocky large breeds like Rottweilers will take longer to reach full size than larger-framed but leaner Irish Wolfhounds. Large breed dogs can take up to 24 months to reach their full frame size and as much as 36 months to reach their full adult body weight!

Diet and Exercise
Though average growth time largely depends on the dog’s breed size and body type, food and activity level can play a huge role in how slowly or quickly your dog grows, and in its eventual adult size. Experts caution against overfeeding puppies, as this can lead to unhealthily rapid growth which in turn can cause bone structural issues into adulthood. Also, while puppies’ bones are still in the growth and strengthening stage, it’s important that they get regular exercise but NOT of the high-impact variety. Running, jumping, and leaping onto hard, non shock-absorbent surfaces may be detrimental to proper bone development. For this reason, you should stick to soft grassy areas and carpet until their bones can take the impact of regular leaping and running on hard ground (around 9 months for small breeds and 14 months for large breeds).

Big Babies and Little Adults
It’s also important to understand that (just like with people!) growth rate doesn’t always match maturity rate. Just because your dog may have reached full size doesn’t mean that they’ve expended all of their “puppy energy.” Energetic herding breeds (like the Border Collie) typically take longer to mellow out than other breeds, regardless of their physical size. Even breeds that are quite similar in size and appearance can have very different maturation rates. For example, Shih-Tzus tend to act like adults as early as 12 months while their Lhasa Apso cousins can often retain their puppy-like personality traits until the age of 3.

By Maya M.