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How Big Does a Border Collie Get? (With Size & Growth Chart)

Melissa Gunter

By Melissa Gunter

Border Collie outdoors

Border Collies are best known for their high levels of intelligence, energy, and beauty. These herding dogs love having a job and excel when you give them one. If you’re interested in bringing a Border Collie into your family, you should know what to expect when it comes to their size. Border Collies are considered medium-sized dogs with males, the larger of the breed, reaching an adult weight of 45-55 pounds.

Let’s take a look at Border Collies and how they grow. This will help you better understand what to expect if you decide to bring a Border Collie pup home and how to ensure your pup grows up to be healthy and strong.

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Facts About Border Collies

border collie
Image Credit: Lucia Horvath Photography, Shutterstock

Border Collies thrive on knowing their job and what is expected of them. These intelligent dogs were bred as herding dogs to ensure flocks of sheep and other farm animals were kept in line and protected. While they are still used for this purpose, they have also made their way into the hearts of families around the world.

Don’t expect this breed to be a couch potato, however. Even as part of a family, Border Collies need tasks to keep them out of trouble. Whether this is long walks, time playing outside, or agility training, it’s important that the minds of these dogs are kept occupied or you’ll find them trying to “herd” the family and other pets around the house.

Even as working dogs, Border Collies want to spend as much time with their owners and families as possible. They are extremely loyal and loving. Like many intelligent dog breeds, Border Collies will need consistent and firm training to ensure they don’t try to run the household.

Interesting Border Collie Facts

  • Border Collies originated from the border between the UK and Scotland which is also where they got their name. The word Collie is used by the Scottish to describe sheepdogs. With Border Collies thriving so well in the borderlands, the name Border Collie was born.
  • Queen Victoria was known as a Border Collie enthusiast. It was thanks to her admiration that the Border Collie was separated from modern Collies and recognized as a breed of their own.
  • Thanks to their high intelligence and incredible work ethic, Border Collies make great search and rescue dogs.

Border Collie  Size and Growth Chart

Border Collie
Image Credit: animalsindistress, Pixabay

It’s difficult to lump every Border Collie together when it comes to their growth. Some will grow faster, while others will take a little more time to fill in. Still, it is great for new Border Collie owners to know an established weight and size range. This will help them determine whether their pup is reaching important milestones or potentially putting on a few more pounds than they should. The below chart is a great estimate of how Border Collies grow throughout their developmental stages.

Age Weight Range Height Range
3 months old 8-15 pounds 10-12 inches
6 months old 15-30 pounds 12-16 inches
9 months old 25-40 pounds 15-19 inches
12 months old 30-40 pounds 18-22 inches
18+ months old 30-55 pounds 18-22 inches

When Does a Border Collie Stop Growing?

Like most dog breeds, a Border Collie is considered an adult at 12 months of age. At this point in their lives, Border Collies have most likely reached their maximum height range but they still have a bit of bulking up to do. Most dogs of this breed will meet their maximum weight between 15 and 18 months. After this, you’ll notice that your pooch isn’t putting on pounds like they did when they were younger.

However, you shouldn’t be shocked if your male Border Collie doesn’t weigh exactly as the chart above states. The same can be said for their height. As we’ve already mentioned, every dog is different. Your Border Collie could be smaller or larger than others you’ve seen. It may also take them longer to meet their maximum size, so don’t worry.

border collie
Image Credit: Jacqueline Galand, Pixabay

Factors Affecting the Size of Border Collies

Just like human babies, not all puppies grow at the same rate. This difference in weights and sizes of Border Collies is thanks to multiple factors including their genetics, diet, exercise, and potential health issues.


Border Collies inherit their genetics from their lineage. If one of your pup’s parents had a bigger bone structure than most Border Collies, your pup may inherit that. The same can be said for small-statured dogs. These types of things are in your puppy’s DNA. You can try to give them extra food or even initiate a diet, but you cannot change your pup’s bone structure and design.


It is important, however, no matter your dog’s genetics, that they are fed a well-balanced, high-protein diet. Unfortunately, Border Collies can be prone to food allergies. To avoid any potential issues, reach out to your veterinarian for recommendations. They will also guide you on how much your dog should be eating daily according to their age and developmental stage.

Border Collie Eating
Image Credit: Alicia Fdez, Shutterstock


Exercise is another big factor when it comes to the size of a Border Collie. These dogs strive for activity. They are very energetic and task-oriented. The more a Border Collie exercises, the more muscle it may build. If you have a dog that wants to be on the go a lot, it may work off a few pounds or even put on more muscle mass. This is common. However, if you notice your Border Collie losing too much weight, reach out to your veterinarian.

Health Issues

Unfortunately, not every dog is going to be healthy while they are growing. Border Collies who suffer from diseases or intense illnesses when they are younger may struggle to reach their ideal weight and size. If this happens to adult dogs, they may lose weight and not be able to gain it back.

Ideal Diet for Maintaining a Healthy Weight

Feeding your Border Collie a healthy diet is one of the best ways to ensure they reach the proper size and weight. Puppies should be fed ½ to 1 cup of high-quality puppy food per day. As a puppy’s stomach is quite small, free feeding should not be allowed. This can cause your puppy to gain too much weight or eat more than it can handle causing an upset stomach, vomiting, or diarrhea.

When your Border Collie reaches adulthood, you’ll find yourself switching to high-quality, protein and calorie-rich kibble. 1 ½ to 2 cups of kibble twice a day is a good feeding schedule. Keep in mind, however, these dogs have a lot of energy and need food that can keep up with them. Active Collies should consume 900 to 1,000 calories per day. Border Collies that work on farms as herders need even more calories and should get roughly 1,400 per day.

When your pet reaches its senior years and isn’t as active as they once were, its calorie intake should lessen a bit. Older Border Collies will need around 700 calories a day to stay healthy. You may also consider switching to kibble which is intended for older dogs.

man buying pet food
Image Credit: BearFotos, Shutterstock

How to Measure Your Border Collie

Like other dog breeds, a Border Collie is measured from its withers to the ground. The withers of a dog are the highest point on its shoulder blades. One of the easiest ways to do this is to stand your dog by the wall, making sure it is standing straight and tall. Feel for your dog’s withers, then make a point on the wall to show where they are. Once this is done, you can let your dog move so you can measure from the mark to the ground. This will give you the best measurements for your dog’s growth.

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As you can see, Border Collies are amazing dogs that grow to medium-sized dogs as adults. For fortunate dog owners who share their lives with these amazing dogs, this information on how your Border Collie should grow can help you know where your pet is in its development. If you’re considering a Border Collie as a pet, this information can help you better understand what to expect.

Featured Image Credit: ForeverNaturalPhotography, Shutterstock

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