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Border Collie Growth Chart: Puppy Milestones & What To Expect


Last Updated: December 18, 2023 | 18 min read | Leave a Comment

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The Border Collie, also called the Border, is an ancient hunting dog breed that has been around since the time of the Vikings. These dogs are known as being one of, if not the most, intelligent canines in the world. They are incredibly skilled at herding, have tons of energy, and are extremely agile. These medium-sized pups make wonderful family companions and are popular worldwide. They are medium-sized dogs and love to be around people. This Border Collie growth chart focuses on the growth milestones of a dog’s first year.

Dog owners often wonder how large and fast a puppy will grow. One question owners often have is, “how big will my Border Collie get?” Understanding that different factors affect every dog’s growth, including genetics, care, lifestyle, nutrition, and health. All dogs have their own unique size, but there are some similarities and growth expectation guidelines for every breed that owners can look to and stay more informed about.

Of course, responsible pet parents want to know what to expect when it comes to the growth and development of their new puppy. Owners are often very concerned that their dogs are developing normally and will want to compare them to others. Our comprehensive guide and Border Collie growth chart gives owners insight into what growth guidelines to expect for the first year. We also answer frequently asked questions about the Border Collie’s growth and development. Growth charts and guidelines like this one are valuable tools to help owners know what to expect, but they are not exact predictions of how fast a dog will grow or when they will reach specific milestones.

What To Expect

Small black tricolor border collie puppy laying on breeder's hands in the garden
Growth charts help owners know what to expect and how to provide the best care possible for their pups.

Growth charts like this one help owners stay informed, as well as provide information on how to care for pups during different growth stages.


This guide describes the average growth patterns for a healthy Border Collie. Full-grown males reach between 40 to 45 pounds and stand 19 to 22 inches tall. Females reach about 27 to 42 pounds as adults and stand 18 – 21 inches tall. They can get as big as about 55 pounds and are athletic, muscular dogs. These dogs fall into the herding category with the American Kennel Club (AKC) and are medium-sized. They can sometimes be found in mixes, adding some unpredictability to size.

Border Collies look somewhat similar to the Australian Shepherd, with the head of a Collie. Their bodies will be longer than they are tall. They can have course longer coats or sleeker, shorter coats, and can be found in a variety of colors, including all black, black, and gray, black and white, red and white, and tricolor. Their tails are slightly feathered.

Border Collies grow until they reach about 15 to 18 months. Most will have the majority of their bulk by the time they reach 12 months but will continue to grow slowly over the next few months until they reach their full adult size. It is not unusual for dogs to continue to fill out until they reach two years old. Even when they physically reach adult size, Border Collies take a long time to mature emotionally. This process can last until they are between three and four years old.

Puppy Growth Timeline

Brown and white Border Collie puppy sitting on a white background
There are many different puppy milestones owners should look out for.

We have developed a general timeline of expected growth for your Border puppy. We provide a small bit of information about the developmental stage dogs are in, as well as explain how they are growing. These topics are covered more in-depth in this first-year puppy guide. Puppies experience growth spurts and lulls and can lose weight from water loss or using the bathroom. Most Border Collie pups will weigh about 16 to 25 pounds by six months old. Females will be smaller.

Birth to 2 Weeks

The first few weeks of life after birth are referred to as the neonatal period. Border Collies will weigh between 7 and 14 ounces at birth on average. Along with being incredibly tiny, their eyes and ears are sealed. They cannot see or hear and will spend the next few weeks as close as possible to mom. Right now, all puppies really will do is nurse and sleep. Around two to three weeks old, eyes and ears will begin to open. Puppies will notice their surroundings and start to interact a little more with their litter mates. They will gain a lot of weight in these first few weeks and anything from one-half an ounce to 1 1/2 ounces daily.

1 Month

By one-month-old, your Border Collie puppy will be quite a bit sturdier. Your pup can see and hear and will be much sturdier on their feet. Puppy teeth should start to grow, which means this is the time to start weaning your pup. Start to offer your fur baby puppy mush. This mixture of high-quality puppy kibble is soaked in water or milk substitutes. This mush is mostly water at this point but will increase in food as your pup starts to eat more of it. Male Borders weigh between 3 and 5 pounds at one month. Females will weigh between 2 and 4 pounds. On average, you can expect a two-to-four-pound weight gain for the next several weeks.

Make sure your pup has regular access to fresh water and puppy mush. Though still young, puppies need to start eating food, as mom’s milk only lasts a few short weeks. Socialization has started, even in very small doses. Your pup will start to learn more about the world and will interact with birthers and sisters, as well as the humans caring for them. They are easily tired and should only venture about in small amounts of time. They will grow bolder and bolder as they get bigger.

2 Months

At two months, pups should be fully on puppy food. This can be a form of puppy mush that is more food than water or puppy kibble if your dog is ready and comfortable to eat it. Some occasional wet food is okay but be careful as it is very rich. Your Border Collie puppy will be about four times the size they were at birth. Males will weigh 6 to about 10 pounds. Females are around 4 to 8 pounds. Puppies are not quite ready to be away from mom, even though they should be weaned.

Right around now, pups start to show a bigger interest in food. They will be very active, learning new things every day. Puppies should head to the vet by the end of two months. It is time for an exam and to get those first puppy shots started.

3 Months

By three months, your puppy will not seem as fragile. It is time to start housetraining. The process will take some time, be patient and positive with this. By now, Border Collies are very sturdy and quite energetic. They will eat a lot and still gain weight, but growth will slow down a bit. Males can weigh between 10 and 13 or so pounds. Females will be smaller, about 8 to 12 pounds.

Your puppy is very similar to a toddler in behavior and thinking right now. Along with house training, your pup should start obedience training. This will be very simple at first but sets the foundations for your behavior expectations. Positive reinforcement works very well. You can introduce puppies to toys, healthy treats, and lots of cuddles. This is also when puppies can start to leave their mom and head to their new homes.

It is important to remember that Border Collies do not like being left alone. They can easily develop separation anxiety. It is recommended with this breed to crate train from a very early age. When bringing home a new Border puppy is a perfect time to start crate training. Setting up a comfy crate that is their safe, secluded spot will help them adjust to their new home, as well as help teach them crate training.

Crate training can be hard, and there may be some whining and crying. If your puppy has plenty of food and water, is in a protected spot, and is nice and comfortable in their crate, they will be safe and sound. Despite the temptation to give in to those adorable little cries, owners must resist. Because this breed is such a high-energy canine, even as adults, crate training is a very important thing to teach them to get used to.

4 Months

At four months old, your pup is a bundle of energy. Growth will be quite obvious, and they will fill out significantly from one week to the next. Puppies will be quite independent by now. They should fully enjoy puppy kibble and treats. This is around the time when puppy teeth will come out, and sharper, sturdier adult teeth will grow it. Be very careful with this highly energetic breed. They are quite playful and tend to be a bit obsessive about their favorite games and toys.

Because pups are teething, you may experience some chewing and mouthing behavior, which might be painful or destructive with those sharper, stronger teeth. Feeding puppies several small meals of high-quality puppy kibble will help keep their energy levels sustained all day and help with those sore gums.

Basic commands like “sit,” “stay,” “come,” and ‘let’s go” can be taught now. Potty training should progress, but your pup will likely still have some accidents. Male pups will weigh between 13 and 16 pounds, and females will follow at 11 to about 14 pounds.

Remember that this is simply an estimation of the average size of Border pups. Yours may be bigger or smaller. This is also a good time to talk with your veterinarian about when you should expect to spay or neuter. For this breed, it is usually when they get slightly older, closer to a year old. However, it is good to have a conversation and set things in place. This usually happens between nine months and a year, sometimes earlier if your pup is smaller.

5 Months

At five months old, your Border Collie pup might resemble a wind-up toy that never stops. They will zip all over the house, full of energy, curious as can be, and always ready to play. Your fur baby should continue to eat several small meals daily as they keep growing and using a lot of energy. Males will weigh between 16 and 20 pounds. Females will be between 15 and 18 or so pounds on average.

This might be a tricky month or two as your puppy will be finishing up potty training and in the middle of teething. It is very important that they socialize with other animals in the home and people. Make sure puppies are up to date on all puppy vaccinations. Depending on your provider’s vaccination schedule, you will likely visit the veterinarian every few weeks.

6 Months

Your puppy is six months old, and you basically have a teenager in the house. Rapid growth has slowed but will continue more slowly over the next several months. You may notice a little bit of attitude to go along with your dog’s high level of energy. Make sure to keep up on daily walks and physical activity. These dogs are incredibly smart and love to play games, so they will easily learn how to play fetch and similar games. Try to find ways to burn off all that energy.

This is a wonderful time to start leash training if you have not done so yet. Stay away from the dog park, as your pup probably still needs more vaccinations and is likely not socialized enough. Males will weigh between 20 and 25 pounds by now, and females will range between 18 to 22 pounds. Females will start to reach sexual maturity around six months. For males, this will happen a little later, starting around seven months. It is important to discuss spaying and neutering with your veterinarian before your puppy reaches sexual maturity, especially for females.

7 Months

By seven months old, your puppy is fairly well-established in routines but slightly clumsy. As puppies are still growing and their bodies change at times, it may seem like they are not fully in control of their limbs. Additionally, puppies should be doing very well on house training and understand basic commands. Puppy vaccinations will be close to being done, and you can explore a little more. Leash training is very important. This breed has extremely high exercise requirements. They will need 60 to 90 minutes of high-activity exercise every single day.

Puppies will still be growing, and you will likely still see bouts of weight gain. Puppy growth can be unpredictable, going through growth spurts and lulls. Right now, male Border puppies weigh between 25 and 28 pounds, while females are slightly smaller, between about 22 and 25 pounds.

8 Months

Right around now, your puppy will start to slow down a little bit. Behavior expectations and routines are old habits. There may be a lot of puppy energy, so training and behavior reinforcement are important. Exercise and burning off physical energy will always be important with the Border Collie. Set routines for this behavior now. Weight gain continues, male puppies are in the 28-to-32-pound range, and females are about 25 to 28 pounds.

Though your dog is maturing and growing older, this breed will require high-intensity exercise throughout their lives. They are bred to be herding dogs. It is in their nature. They do not fare well when left home alone all day. They will become incredibly destructive. If you must leave, having a designated room or crate train them is a good idea. If you must do this, make sure your dog has an opportunity to expend some energy first. Keep a wide variety of toys and games around and constantly rotate new ones.

9 Months

At nine months old, your pup should have most adult teeth grown in. You may see some limits being tested behaviorally around now. Puppies will start looking more like adult dogs than little puppies. Regular weight gain continues, and you may still see some periods of rapid growth. Males weigh between 33 and 35 or so pounds. Females are in the 26-to-30-pound range.

Your pup still needs to be on puppy-formulated food. They are still growing quickly, and this breed is incredibly high-energy. Three to four small meals a day of high-quality food is best. Puppies should always be fed kibble, but you can mix in fresh and canned meals, as well as plenty of treats. This is also the time when a decision will need to be made about when to spay and neuter if that has not been done already.

10 Months

Your puppy will be incredibly independent by ten months old. Routines are important at this age, especially because your pup’s inclination for testing limits is not over yet. It is very important that your dog be properly leash trained. If you are having trouble, it is time to contact your vet and get some help. Puppy vaccinations will soon be over, opening your dog to more adventures. Borders are incredibly high-energy, so you may not see a slowdown in activity that happens around this time with some other breeds.

You should still see some regular weight gain, about half a pound to a pound a week. Males weigh between 35 and 38 pounds, and females weigh between 28 and 32 pounds. Regular grooming and dental care should be part of your pup’s routine. Dental care is often overlooked, and it is better to train your dogs to get their teeth cleaned young to prevent dental disease.

11 Months

At 11 months old, not much is changing. Pups will continue to mature and put on a little weight. By now, puppies should be fully housetrained and have well-defined behavior expectations. Borders are very energetic, and this will not change, so your pup will continue to need a lot of attention and exercise.

However, by now, plenty of games can be taught, as well as options for entertainment at home. These doggos will need more than just a quick walk around the block. Expect to spend at least an hour a day in high-intensity physical exercise. These pups will need to run and love to play chase, catch, and other games where they can exert much energy.

This is a good time to consider adding a little bit of adult kibble to your dog’s puppy chow. Over the next several weeks, your dog will start transitioning to adult food. Do not make this switch suddenly. It is a process that will take place over a couple of months. Male Border Collies weigh between 38 and 42 pounds and females between 32 and 36 pounds.

One Year

Yay! Your pup has made it one year, and this is cause for a lot of excitement. Your puppy is now considered an adult dog, although you will still see some weight gain and filling out for the next several months. This process can actually go on until they reach about two years old.

Just like Border Collie puppies, adults are very high-energy. By now, all puppy vaccinations and exams should be done, and you are free to take your dog with you to the dog park, on hikes, or anywhere that is canine-friendly. Your pup has mainly reached adult size, but you can expect to see some filling out for the next few months. Slow weight gain can happen up until they reach about two years old. Your dog has not quite yet reached mental maturity, even though physically, they are adult.

Males weigh between 35 and 45 pounds at one year, and females weigh between 30 and 40 pounds on average. Though you will not see much significant weight gain unless a pup is overeating, dogs will continue to fill out in bulk and height slowly over the next six months.

2 Years

By two years old, your pup should have reached physical and mental maturity. Males can weigh anywhere between 40 and 55 pounds by two years old, and females follow between 30 and 45 pounds. This is a large range. Some Borders are much smaller than others. Those with mixed bloodlines may also grow larger than purebred pups.

What Happens Next

It is commonly thought that once dogs reach a year old, they stop growing, but this is not exactly true. Though they are considered adults at this time, they still have some growth and mental maturing. If you are concerned about your dog’s growth, you need to contact your veterinarian. Once your dog celebrates that first birthday, it is important that the transition to adult food starts.

Puppy-formulated food is higher in fat and calories to support their rapid growth and energy usage. Adult dogs do not need as much fat and will happily eat puppy food but will quickly become overweight. Your Border Collie should continue to eat several, three, to four small meals throughout the day rather than two large ones. This breed is high-energy, even into senior years, and will need periodic replenishment of calories and energy.

Full-Grown Border Collie

Border collie playing with toy ball on couch indoors
Expect to spend at least an hour to an hour and a half each day in highly interactive physical exercise.

A full-grown Border Collie will be somewhat calmer and more well-behaved than puppies. These pups are high-energy but will understand they will get outdoor playtime. These dogs are incredibly intelligent and catch on quickly to new games and training.

As with all dogs, they can be a little independent. Even adults do not like to be left home alone, so you must continue creating them when you leave. This is important because these pups are notorious for chomping on furniture, shoes, clothing, and just about anything they can get their teeth on. When left home alone without being in a safe, restricted area, they can be quite destructive.

Border Collies live between 12 and 15 years on average. They will need regular exercise throughout their lives. These dogs need mental and physical stimulation throughout their lives to stay healthy. Periodic training and behavior reinforcement may be helpful. Because they are so intelligent, even adults can have an independent streak. Continue to reinforce behavior expectations even after your dog celebrates their first birthday.

Border Collie Growth Chart Height & Weight

AgeMale Weight (lbs.)Female Weight (lbs.)
Birth to 2 weeks7 - 14 ounces7- 14 ounces
1 month3 - 52 - 4
2 months6 - 104 - 8
3 months10 - 138 - 12
4 months13 - 1611 - 14
5 months16 - 2015 - 18
6 months20 - 2518 - 22
7 months25 - 2822 - 25
8 months28 - 3225 - 28
9 months33 - 3526 - 30
10 months35 - 3828 - 32
11 months38 - 4232 - 36
1 year ( 12 Months)35 - 4530 - 40
2 years (24 Months)40 - 5530 - 45
HeightMale & Female
2 Months2 - 10
3 Months10 - 12
6 Months12 -16
9 Months16 -19
12 Months19 - 22

Factors To Consider

Puppy dog border collie and stethoscope isolated on white background
Several different things will impact how big a dog of any breed gets.

Breed and specific bloodlines are some of the most significant, along with nutrition and care. Growth charts like ours and puppy milestones are wonderful reference points for owners to look to. They help us know if our dogs are developing along the right path as others of the breed. However, remember that these are not exact predictions or absolute measures of how large or small any specific dog will be.

Dogs will reach the right size for them. As long as they are not overweight or unhealthy, owners should not be overly concerned. Always discuss any concerns with your veterinarian sooner rather than later. If you are concerned about your dog’s growth, whether a puppy or an adult, seek out advice from your veterinarian.


Genetics might be considered the most significant factor around how large any canine breed will grow. Within the breed, bloodline matters. Oftentimes, mixed breeds grow larger than purebreds. owners can look at the parents of their specific dog, if possible, to get a better idea of how large they might grow. There is no surefire way to predict exactly how large a specific dog will be. This breed has no genetic predisposition to any medical issues that might impact size.


Along with genetics, nutrition is a significant factor in how large Border Collies grow. Canines should eat a diet that has plenty of healthy animal proteins, fruits, vegetables, and healthy grains. Healthy protein choices include chicken, turkey, lamb, beef, salmon, venison, duck, and rabbit. Try to feed your pup food that is natural and does not use fillers or artificial flavors and colors. Remember, your dog needs to be on puppy food exclusively until they reach about a year old.

Stick with higher quality foods if possible, and avoid budget brands that use unnamed meat sources, unnamed meat byproducts, or use wheat gluten and lots of corn as fillers.

Growth Spurts & Plateaus

Dogs, just like human children, will experience growth spurts and plateaus. Sometimes it will seem like they put on ten pounds a week, and other times they seem not to grow at all. Remember that growth spurts and plateaus are perfectly normal, and they can happen at any time. These are incredibly unpredictable and can sometimes make owners concerned.

If you are concerned about your dog’s growth patterns, discuss this with your veterinarian. They can help look closely at your dog’s nutrition and rule out any underlying issues that might be impacting growth.

Neutering & Spaying

Neutering and spaying a pup do have an impact on growth and development. While doing this too early on will not necessarily impact size, it can affect lifelong health. Namely, doing this too early can delay bone growth and impact joint health. Make sure to talk to your veterinarian about the right time to undergo this procedure for your pup. Border Collies should not be spayed or neutered until at least six to nine months old, and many veterinarians prefer to wait a little longer.

Physical Health & Activity

Dogs who are physically healthy with proper nutrition will grow bigger and stronger. Canines with poor nutrition or underlying health disease may seem not to grow rapidly or have trouble gaining weight. Dogs who are inactive and do not get enough exercise may start to gain weight and lose muscle tone. Conversely, dogs who are too active and get too much exercise can overwork themselves and cause muscle soreness, exhaustion, and mobility issues.

Physical health is very important to proper growth and development. Physical health depends upon the level of care a pup receives. Regular medical attention and proper nutrition will help keep dogs in tip-top shape regarding their physical health. Dental health is an often-overlooked part of physical health but should be part of a dog’s daily or weekly routine.

Border Collies are overall a very healthy breed, though they can be prone to some health conditions. These include hip dysplasia as well as different eye diseases. This breed can also suffer from epilepsy and hypothyroidism. Because of this, it is very important to keep up with your dog’s regular veterinary appointments, especially preventative care. These routine checkups are when owners and veterinarians can discuss a dog’s development, as well as any smaller issues. This is where veterinarians can identify and start treatment for conditions before they become very serious.

Frequently Asked Questions

Portrait of amazing healthy and happy black and white border collie puppy sitting outside
Here are some common questions you might be wondering about Collie’s growth.

Are Border Collies small or medium-sized dogs?

Border Collies are medium-sized dogs. They rarely get over 45 or 50 pounds unless they are a mixed breed.

How big is a full-grown Border Collie?

A full-grown Border can weigh between 30 and 55 pounds and stand between 18 and 22 inches tall. Males are larger than females. Remember that they gain weight slowly for almost a year after they are considered fully grown.

Are Border Collies good dogs for apartments?

Due to their high energy level and dislike of being left home alone, this is not the best breed to keep in a small apartment. These dogs need access to a yard or space where they can run. This is very important for their physical and mental health. Because these doggos are so high in energy and do not like being left home alone, they can also be loud and destructive. This does not bode well in close living quarters or apartment buildings where they might be surrounded on all sides by neighbors.

Are Border Collies smaller than Standard Collies?

Yes, Border Collies are somewhat smaller than Standard Collies. Standard Collies stand between 24 and 26 inches tall and weigh between 60 and 75 pounds when fully grown.

Final Thoughts

Border Collies are highly energetic, extremely intelligent, affectionate dogs who make wonderful family pets in the right situation. They are medium-sized and reach between 30 and 55 pounds when fully grown. 55 pounds is on the larger end, and males will be larger than females. Remember, this breed will continue to grow after they reach one year old, even though, at this time, they are considered adult dogs.

Even though they will physically stop growing and start to behave more like adult dogs, the Border Collie is extremely energetic and will remain so throughout their life. Because these dogs are medium-sized, they appeal to many people. However, they do need homes with lots of room to run about. Physical exercise is incredibly important for this breed, and they need more than just a walk around the block. Though they may not be the largest breed around, these pups will make a huge impact on your life.

It is important to know what growth milestones to look out for, and our Border Collie growth chart offers owners a guideline to refer to and know what to expect. Always make sure to consult your veterinarian about any specific health or growth concerns you may have.


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The information provided through this website should not be used to diagnose or treat a health problem or disease; it is not intended to offer any legal opinion or advice or a substitute for professional safety advice or professional care. Please consult your health care provider, attorney, or product manual for professional advice. Products and services reviewed are provided by third parties; we are not responsible in any way for them, nor do we guarantee their functionality, utility, safety, or reliability. Our content is for educational purposes only.

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