How Big Will My Puppy Get?

Does he have to grow up? 🥺

growing puppy

Puppies are so cute and small that you may want yours to never grow up. But eventually your puppy’s going to get bigger — but just how big, exactly?

We spoke to Dr. Sara Ochoa, a veterinarian consultant at Senior Tail Waggers, and Dr. Zay Satchu, cofounder and chief veterinary officer at Bond Vet in New York City, to find out how to tell how big your puppy will get and when he’ll stop growing.

Factors that influence how big your puppy will get

There are actually a bunch of factors that affect how big your puppy will be when he’s full grown.

“With purebred dogs, we can estimate based on breed standards and averages of Mom and Dad,” Dr. Satchu told The Dodo. “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.”

Here are some things you should take into account when estimating the size your puppy will be when he’s all grown up:

  • Breed — Breed is a major factor when determining how big your puppy will be, since there’s a huge difference in the size of a Great Dane compared to a dachshund.
  • Parents — If you know your dog’s parents, you can estimate how big your puppy will be based on an average of their sizes.
  • Gender — Males typically grow to be larger than females.
  • Neutering and spaying — If your puppy was neutered or spayed at a young age, he or she might weigh slightly more. Neutering causes a reduction in sex hormones that can lower your puppy’s metabolism, causing him to gain weight if you don’t adjust his diet after the procedure.
  • Diet — What you feed your dog and how much you feed him can impact his size and growth. Be sure to feed your pup a healthy and complete puppy food that has enough nutrients to help him grow to his full size. Try this Purina Pro Plan puppy food from Chewy for $50.
  • Exercise — How much exercise your puppy gets will affect how much he weighs. If you don’t exercise him enough, he could become overweight.

Puppy size estimator

Since breed or breed mix is a big factor in how big your puppy will get, you can use that to help determine your puppy’s adult size. Here are some average adult weight ranges of different-sized dogs:

  • Toy dogs — 2 to 15 pounds. Toy dogs include Pomeranians, Chihuahuas, Yorkies and pugs.
  • Small dogs — 16 to 25 pounds. Small dogs include Shelties, French bulldogs and beagles.
  • Medium dogs — 26 to 50 pounds. Medium dogs include Border collies and cocker spaniels.
  • Large dogs — 51 to 100 pounds. Large dogs include Malinois, Labs, German shepherds and Irish setters.
  • Giant dogs — 100+ pounds. Giant dogs include Great Danes, mastiffs and Saint Bernards.

When do dogs stop growing?

Puppies grow and mature at different rates, so they’ll reach their full size at different times. When puppies finish growing depends on their size. For example, small dogs grow faster than larger breeds because big dogs have bigger bones that need more time to develop.

“This may be at 6 to 8 months for smaller dogs (25 pounds or less), 12 to 16 months for medium-sized dogs (25 to 75 pounds), and 2 years for large- and giant-breed dogs (over 80 pounds),” Dr. Ochoa told The Dodo.

Here’s an average of when dogs will typically be done growing based on their size:

  • Small dogs (25 pounds or less) — 6 to 8 months old
  • Medium dogs (25 to 75 pounds) — 12 to 16 months old
  • Large and giant dogs (over 80 pounds) — 18 months to 2 years old

Even though you might want your dog to stay a puppy forever, he’ll have to grow up some time. And knowing how big he’ll get is important so you can get the right dog supplies and make sure you have plenty of room for him.

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