How Big Does A Border Collie Get?

Border Collie standing

Dogs have been known as ‘man’s best friend’ for a very long time. The domestication process from the wild wolf’s relative to that drooling, loveable idiot who knocks over his food bowl in excitement every morning when you come down the stairs has taken between six and nine thousand years! 

These days, dog ownership levels have never been higher. The Border Collie is undoubtedly one of the world’s most popular dog breeds. 

So for many aspiring owners, the first question that springs to mind before taking the plunge and getting a new puppy or rescue dog companion is: 

How big does a border collie get exactly? An adult Border Collie weighs between 30 to 45lbs (or around 13 to 20kg for our European friends). They get between 18 to 22 inches (45/55cm) in height, depending on your dog’s gender. 

In more general terms, border collies can reach about the mid-height of an average person, which would probably qualify them as a mid-size dog in most people’s books. 

While they’re no Rottweiler or Great Dane (although I’m sure some owners will tell you their energy levels and appetite can certainly more than makeup for it!), Border Collies are still definitely big enough to be more than a handful. 

Let us look a little deeper at just how big that is. Whether it’s to help you understand if a Border Collie could be the new best friend you’ve been looking for, or if you’re just looking to improve on your general knowledge of the breed, this article should answer all your queries on how big Border Collies can get.

How heavy Do Border Collies Get?

Although they’re not the heaviest of dog breeds by any stretch, a fully grown adult Border Collie can still weigh as much as 30 to 45 pounds. I’m sure you’ll agree it is still more than heavy enough when your canine friend comes bounding up onto your lap excitedly when you weren’t expecting it! 

That’s about as much as a small child, and comparable with other herding breeds like the Australian Cattle Dog and Finnish Lapphund, for reference.

Their high energy personalities and natural love of exercise means that Border Collies sure can plow through food every day in order to power their next venture, also. 

Although they have an average metabolism speed for most dogs of their size, Border Collies can require anywhere between 700/1400 calories per day, depending on their age and size. Which shows just how much energy they can expend running around every day. 

This is almost as many calories as a Great Dane uses daily despite Border Collies being much smaller in size.

At What Age Are Border Collies Fully Grown?

Border Collies, like most other dog breeds, usually reach their fully grown adult size, along with sexual maturity, somewhere in the first 1 to 2 years of their life. It is relatively quick in the life cycle when compared with human beings and certain other types of other mammals. 

At what age your Border Collie has reached full size, and weight can potentially be affected by a number of factors such as your dog’s overall health condition, diet and lifestyle, and its day-to-day environment.

All individual dogs vary in their growth rates, just as human beings do. Some Border Collies seem to reach full size as quickly as 6-7 months old. 

Although they may have reached full physical maturity by this age, many psychological and structural changes continue to happen in the dog’s brain. In the following years, as it develops to becomes a fully-fledged adult.

Stages Of Development Of Border Collies

Border collies, just like all dogs, go through several key development stages in their life cycle. They are generally considered a genetically healthy breed. They can live for between 10-14 years on average, although 16-17 years is not uncommon. 

Indeed, one of the world’s oldest recorded dogs was a Border Collie from the UK, known as Bramble, who lived to be the ripe age of 25 years old! 

Despite these fairly long lifespans, Border Collies go through the majority of the developmental stages of growth and learning social skills in the first few months of life as a puppy. 

They are only reaching maturity and their full size and weight somewhere between 1-2 years of age. The adolescent period between 6 to 18 months old will see your dog undergo a growth spurt and a sudden burst of hormones just as a human teenager does. 

It can lead to a lot of challenging behavior for their owners at this time. 

Changes in your dog’s size and temperament can be difficult for anyone to manage, especially for the underprepared. The dog may suddenly require much more food, living

space, daily exercise, and even mental stimulation from activities such as playing basic games and obedience training tasks. 

All of these can be hard to manage if you don’t anticipate the timing of these changes within your dog’s lifetime.

Male And Female Border Collie Growth Differences

There are very slight variations in the size and weight your Border Collie may reach, depending on its gender. Adult male Border Collies are usually a few pounds heavier than a female of the same age. 

Besides the slightly increased size and weight, male Border Collies otherwise share the same stages of development and growth as the breed’s female. 

Growth in both male and female Border Collies follows the same gradient curve, which increases sharply around the age of sexual maturity as the body produces new hormones to stimulate this.

How Big Is Too Big For A Border Collie?

We’ve, by now, seen the average size of a Border Collie is usually around 18/22 inches in height and 30/45 lbs in weight, but there are some notable exceptions, such as an American Collie who purports to be world’s largest. 

Luckily for any owners of chunky Border Collies who have already gotten ‘too big’, the breed is also known for its strong intellectual capacity and learning ability. 

So there are lots of creative ways an owner could devise to hit a daily exercise target. Over the years, many Border Collies have wowed TV and internet audiences all over the world, not only sheep herding but also exercising a host of other talents such as flyball, swimming and even forming human-dog pyramids! 

So there are no excuses for owners who’s dogs get a little too big, or should we say heavy; get out there and work that weight off, your dog will be sure to love the attention and exercise!

Can The Size Of A Border Collie Deviate?

Due to their relatively stable breed genetics, Border Collies mostly tend to fall within the sizes we first examined earlier in this article, but of course, there are always exceptions to every rule. 

We’ve already looked at an American Border Collie claiming to be the world’s largest. Unfortunately, finding the world’s smallest purebred Border Collie to see just how far the breed deviates from its average size, is quite difficult. 

Although breeders have managed to create smaller and larger dogs that feature the Border Collie’s tri-color coat by selectively breeding runts or crossing them with different-sized breeds of dogs, these methods can be associated with negative health consequences. 

In comparison with some other well-known breeds such as the Daschund or Schnauzer, the Border Collie doesn’t have a significant size deviation from smallest to largest individual animals. 

This is likely due to all modern-day Border Collies being a descendent of a single dog known as Old Hemp, who helped cement the reputation of the breed for livestock herding with a streak of wins at competitions in the late 19th century.

This common ancestor is likely because Border Collie’s are generally all of a similar size and weight once they reach adulthood by comparison with other breeds.


So if you didn’t know how big a Border Collie could be, now that we’ve delved a little deeper into some basic characteristics of the breed and its size, hopefully we have helped to answer that along with a lot of the questions a first time dog owner may have.

The sections listed here in this article are only a small number of the kind of questions any pet owner and animal lover must ask themselves when becoming responsible for an animal. 

I’ve hopefully helped a few people to decide that a Border Collie could be the furry best friend for them.

Erwin Borgers

Hi, I’m Erwin. I grew up with two cats, but I always wanted to have a dog. Since my wife and I lived together, we have Mayla. She is a very sweet King Charles Spaniel. Together we spend countless of hours in the forest near our home. We love to walk together and now I want to share what I learned about walking dogs and what I learned about dog gear with you.

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