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How Big Do Border Collies Get? [When Do They Stop Growing?]

Knowing the size at which a border collie will get, and by what age, is useful information for any prospective owner. It helps you to prepare ahead of time, set expectations, and know how to best look after this breed of dog. Here is the information you need.

So, how big do border collies get? Male border collies stand at 19 to 22 inches in height at the shoulder and weigh between 30 to 45 pounds, on average. Female border collies are slightly smaller standing between 18 to 21 inches at the shoulder and weighing between 28 to 40 pounds.

Border Collie Size

The border collie breed thrives on activity and busyness.

They need enriching activities in their day, or else they will become bored, which leads to irritating behavior like barking, chasing, or digging.

These dogs were bred to work hard all day herding sheep.

Suffice it to say; these canines are workaholics that are in their element when given a job to do, especially if that job involves herding.

Aside from herding, Border Collies excel at many canine sports, mainly because they were bred for endurance.

Border collies are categorized as medium-sized dogs, but what does this mean exactly and what are some more specific measurements you can expect in height and weight?

Particularly by certain stages of their lives.

Let us now delve deeper to give you a better understanding.

How Big Will My Border Collie Get?

The border collie grows into a medium-sized dog, starting life as an adorable little puppy.

They tend to grow quickly, packing on several pounds a month for the first 16 months of their lives.

The following table provides you with the average weight for each sex across the first 16 months of life:

Border Collie Growth Rate

AgeMale Border Collie
Average Weight
Female Border Collie
Average Weight
3 Months6-7 kg (13-15 lbs)5-7 kg (11-15 lbs)
4 Months 7-10 kg (15-22 lbs) 6-9 kg (13-19 lbs)
5 Months 9-13 kg (19-28 lbs) 7-12 kg (15-26 lbs)
6 Months 11-14 kg (24-30 lbs) 9-13 kg (19-28 lbs)
7 Months 12-16 kg (26-35 lbs) 10-15 kg (22-33 lbs)
8 Months 13-18 kg (28-39 lbs) 11-16 kg (24-35 lbs)
9 Months 13-18 kg (28-39 lbs) 12-16 kg (26-35 lbs)
10 Months 13-18 kg (28-39 lbs) 12-17 kg (26-37 lbs)
11 Months 13-18 kg (28-39 lbs) 13-17 kg (28-37 lbs)
12 Months 14-19 kg (30-41 lbs) 13-18 kg (28-39 lbs)
13 Months 14-19 kg (30-41 lbs) 13-18 kg (28-39 lbs)
14 Months 14-20 kg (30-44 lbs) 13-19 kg (28-39 lbs)
15 Months14-20 kg (30-44 lbs) 13-19 kg (28-39 lbs)
16 Months14-20 kg (30-44 lbs) 13-19 kg (28-39 lbs)

As you can see, a male border collie will typically weigh more than a female border collie. You’ll also notice that there is some variance between border collies of the same age.

This will be largely down to genetics, but will also include other factors like how they are cared for and the quality of diet consumed. Either underfed/overfed dogs are likely to lean towards the extreme of each end.

Here are some key takeaways from the growth table above.

Female Border Collies

  • The average female border collie at 3 months of age will be between 5-7 kg (11-15 lbs).
  • The average female border collie at 6 months of age will be between 9-13 kg (19-28 lbs).
  • At one years old, the average female border collie will be between 13-18 kg (28-39 lbs).

Male Border Collies

  • The average male border collie at 3 months of age will be between 6-7 kg (13-15 lbs).
  • The average male border collie at 6 months of age will be between 11-14 kg (24-30 lbs).
  • At one years old, the average male border collie will be between 14-19 kg (30-41 lbs).

What Age Is A Border Collie Fully Grown?

On average, border collies reach their full-sized adult weight and height by the time they are one year old; some grow faster and reach their mature weight and height as early as ten months but this is the exception rather than the norm.

These dogs have growth plates that close anywhere between 12 to 18 months old. It is safe to say that these dogs become full-grown adults (at least physically) when their plates close and this is when you can roughly expect them to stop growing.

Even after these dogs have reached their adult size, border collies continue to fill out and deepen in their chest, usually until they are 2 1/2 to 3 years of age.

An important thing to remember with border collies is that it takes time for mental maturity to catch up with their size.

It may take longer for them to begin to think like adult dogs instead of puppies, this can occur between the ages of 2 to 3 (or even older).

You must also be aware that there are several kinds of border collies; those bred purely for herding and those bred to enter as dog shows.

Show dogs tend to be on the smaller side compared to their herding counterparts with blocky physiques and heavy coats.

If you wish to select a dog for herding skills, recognize the dog by how they work and not how they look.

Border collies are highly intelligent, and they are keen observers; they are full of energy, and they thrive on early socialization.

Expect some juvenile and puppylike behavior for some years to come with this breed; life will never be dull.

Puppy behavior can be somewhat tolerable except when your dog starts nipping at you or children – this is when things can become problematic.

The best way for a dog to mature is to have proper dog training, where your dog can learn to manage his feelings a bit better.

Factors That Influence Size And Growth Potential

Not every border collie reaches the average full adult size; there are various reasons why a border collie might not develop in the way that they should.

For example, specific canine health complications can inhibit growth. While there is nothing you can do, if they do inherit these defects your dog will not be the weight and size they would be without them.

On the other hand, a puppy that is not fed the right diet or overfed might make them grow too quickly and gain too much weight.

Let’s explore some of the factors that undoubtedly impact the size and growth potential of your dog in more detail.


Some border collies tend to suffer from specific health problems such as epilepsy, CEA, and hip dysplasia.

These genetic diseases will undoubtedly influence the growth and development of a young pup.

Too often, these conditions are not detected early enough. In such cases, a dog will go without treatment that would otherwise ensure they develop well.

For this reason, if you suspect that your border collie is suffering from a particular health condition, is in pain or appears to have stunted growth – speak to your vet.

They will be able to run some tests and an examination and may be able to help your dog overcome difficulties and challenges preventing them from growing as they should.

Its also important to consider that a puppy with health issues may be unable to exercise as they would like to and should.


Diet is a leading factor in how a dog grows and develops; being underfed is just as bad as being overfed.

Overly processed food is never suitable to give your dog.

You must provide your dog with a balanced diet; it must be appropriate for their size and age to ensure that are healthy and grow optimally. It’s a fine balance between raising a dog that is malnourished and emaciated or growing too quickly and overweight.

For this reason, it is imperative that you purchase a high-quality dry dog food feed and follow the manufactures instructions as to how much you should feed. This will be calculated on the size and age of your dog.

Additionally, it is a good idea to talk to your vet about your dog’s own unique requirements and give them the amount of food advised.

Be careful when providing scraps – both in quantity and the types of food offered. Not all foods are appropriate and it is easy to overfeed when providing high-calorie foods.


Border collies need lots of exercise; it is in their genetic makeup and how they have lived for generations. You therefore cannot have them lying around all day.

This breed needs to get outside and run, stretch their legs and work their muscles.

Exercise helps border collie puppies to grow to a healthy weight and size. It is good for their joints and bones, plus it helps to manage and prevent weight gain.

While a border collie will benefit from a minimum amount of exercise, 1-2 hours per day, every border collie is different and will require a different amount of daily exercise.

Typically the younger they are the more erratic energy they will have. Although this is not a breed to really calm down with age.

When owning a border collie, they very much adapt to the amount you give them. So if you walk them for 3 hours per day that is what they will learn to expect.

Scheduled walks are a good way to give them the activity they need. However, letting them run around in open space (such as your backyard), and playing fetch with a ball launcher is a good way to keep them entertained.


Like all dogs and animals for that matter, border collies need a sufficient amount of sleep and rest in order to grow optimally.

Younger pups will often sleep more and this is to be expected.

Providing your dog with a comfortable environment to sleep will ensure they can get the hours they need. There are specific beds (like this ideal one from Amazon), which will ensure your border collie is relaxed and able to sleep.

Be sure to refrain from regularly waking them up, make sure there are no lights/loud sounds or drafts, and try to get them to stick to a sleep/wake schedule.

Adequate sleep will ensure optimal growth and development.


The border collie was initially developed to work as a sheepdog in the border between Scotland and England. These dogs controlled sheep with their famously intense stare.

The border collie isn’t a large breed by any means, but it is very lively with a personality bigger than its size.

Aside from herding sheep, border collies herd many other animals that include cats, dogs, squirrels, deer, and rabbits; these tenacious dogs are even known to herd lawnmowers.

Border collies deserve to live a good life with as few stressors as possible this will help them to thrive and become the healthy energetic dogs they were born to become.

How big do they get you ask? Well, adult males are between 30 to 45 pounds in weight, and their female counterparts weigh between 28 to 40 pounds.

Border collies are medium-sized dogs, but they require lots of space.

If you have ever owned one, you will know how insanely active they are. They just love to play, and small space will never do for these lively companions.

Related Questions

Do Border Collies Make Good House Pets?

Border collies are not the most ideal breed for a house pet. They require a lot of activity, mental stimulation and do not do well in confined and locked-up spaces. Border collies require a lot of interaction and stimulation. Therefore, you need to give them regular and routine access to the outdoors. if you have a lot of open space (including a large backyard), time, and the ability to provide frequent walks and exercise, the

Do Border Collies Bark A Lot?

Border collies are known to bark a lot. They bark as a way to communicate, particularly with their owners, and typically do so when they are bored, stressed, fearful, excited, curious, lonely, and/or feeling playful. Providing frequent stimulation, activity and company are good methods to reduce barking.

Do Border Collies Like To Cuddle?

Border collies are affectionate dogs that like to cuddle their owners. This breed of dog will often look for your company, and will actively attempt to get you to participate in play and games.

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