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When Are Large Breed Dogs Full-Grown?

Large Breed Rottweilers Growth

Am I there yet?

Do you love large breed dogs as much as we do? Here at the Large Dog Boutique we have turned our love for bigger canines into an oversized pooch resource. Anything you need to know about big dogs you will find right here. One question that many big dog owners ask is, “How can I tell when my large breed dogs are fully grown?” That’s a sensible question, so let’s get started answering it for you.

Defining Large Breed Dogs

First, let us get some definitions out of the way. If your dog is 80 pounds or lighter, then she/he is either considered a medium or small pooch. Large breed dogs are classified as those over 80 pounds when they reach maturity. Depending on the type of dog you own, adult size can be achieved in as little as 12 to 24 months.

First-time owners of large breed dogs are often blown away by how fast their big puppy is growing. They foresee a future full of all of the concerns related to having a giant animal in their house. They begin to wonder if their huge ball of fur is ever going to stop growing! Don’t worry, this massive growth spurt doesn’t last forever.

Small dogs like beagles can reach adult size in as few as 6 to 9 months. But large breed dogs are bigger, so there is a lot more growing going on. For instance, a Great Dane can weigh as much as 30 or 35 pounds just 3 months after birth. In only the next 90 days, that weight can shoot up to 70 or 85 pounds. Adult size is usually reached in the 12 to 18 month time range (115 to 130 pounds).

You may think that is awfully quick to reach adult size.

But you can’t compare a 1-year-old large breed dog to a 1-year-old human. The wonderfully informative website PetMD reminds us that 1 year old large dogs have lived the equivalent of 15 human years! And by the time large breed dogs like Mastiffs, Pyrenees and Old English Sheep Dogs are just 2 years old, they have experienced a full 21 human years of life.

Since 21 years is roughly when human beings reach their full physical size, the comparison to large breed dogs in that equivalent of dog years makes sense. This means that your puppy food grocery bill should start to taper off and even go down in size after your big pooch is about 18 to 24 months old.