When Will My Puppy Stop Growing?

If you have an adorable new puppy and you’re wondering when exactly he’s going to stop growing, you’re not alone.

Wanting to know just how big your dog will get is one of the most common questions new dog owners have — and despite what you might have heard, the answer is based on more than just his (super adorable) puppy paw size.The Dodo talked to Dr. Zay Satchu, cofounder and chief veterinary officer at Bond Vet, and Dr. Sara Ochoa, a small-animal and exotic-pet veterinarian based in Texas, about how you can gauge how big your pup will get and what factors may contribute to his overall growth.

First things first: When do dogs stop growing? “Most dogs reach their full size by 18 months of age,” Dr. Satchu told The Dodo, though some dogs, depending on breed, may reach their full adult size at 12 months. “Larger breeds tend to take longer than small breeds to reach their adult weight,” Dr. Satchu said.

Medium-sized breeds, for example — like Australian shepherds — reach their adult size around the 18-month mark, while giant breeds — like Newfoundlands — can keep growing for up to three years.

So if you find that your puppy’s STILL GROWING after a year — even though you’d assumed he’d be done by then — you might have a full six months more of potential growth spurts to look forward to.

According to Dr. Ochoa, you can tell when your dog has stopped growing if you keep a weekly weight and measurements chart that includes height and length.

“Most puppies will continue to grow weekly until they hit their adult size,” Dr. Ochoa told The Dodo. “An easy way to tell if your dog has stopped growing is to weigh and measure them each week. When they stop gaining weight and growing in size, you will know that they are done growing.”

According to Dr. Satchu, this is a very common question — but it’s also one of the most difficult to answer.

“With purebred dogs, we can estimate based on breed standards and averages of Mom and Dad,” Dr. Satchu said. “With rescue dogs, it can be more challenging because we don't know what their ancestral history is and often don't know about the size of Mom and Dad.”

But one trick that Dr. Satchu suggested is jotting down your pup’s 6-month weight and doing a little math. “You may be able to get a general estimate by doubling their weight at 6 months of age and +/- 5 to 10 pounds, but this is still very unreliable,” Dr. Satchu said.

In other words, you might still be surprised!

While it’s not completely accurate, a popular opinion is that larger paws indicate that a puppy will be supporting a taller and heavier build, whereas smaller paws indicate a smaller build. While this isn’t backed by science, it’s still fun to consider when you’re playing the “How Big Will My Puppy Get?” game with your friends.

How large your puppy will get depends on several factors, like genetics and nutrition. For example, if your dog’s parents are a larger size, there’s a good chance your puppy will be, too.

The quality of your puppy’s food will also play a role. “One of the main things that affect the growth of your puppy is nutrition,” Dr. Ochoa said. “If your dog is eating a healthy diet, they will be able to reach their full growth potential.”

Feeding your dog high-quality food will ensure he reaches his maximum growth potential. Otherwise, a dog with poor nutrition might be weaker or smaller than they could otherwise be. Your vet can give you some good recommendations as to which puppy food is best for your pup’s weight, size and breed.

While it might be fun to try to guesstimate your puppy’s potential adult size, your best bet is to just wait it out and see. He’s one of a kind, after all!