How big can a Border Collie get?

how big can a border collie get

Before you get a dog, you should think about all sorts of things so as not to experience any unpleasant surprises later. One important point is how heavy and how big a Border Collie will be.

A Border Collie is full grown with about 1 – 1.5 years. He then has a weight of about 31 – 44 pounds (14 – 20 kg) and reaches a withers height of 48 – 56 cm. The females, as with all dog breeds, remain somewhat smaller and lighter than the males. So, the Border Collie is smaller and lighter than many other popular dog breeds.

How fast does a Border Collie puppy grow

When your puppy has moved in, you will probably be concerned about whether it is healthy and growing and gaining weight normally.

If your puppy grows significantly slower, this may have health reasons that you should discuss with your veterinarian. However, the values given here are only a rough guide for orientation.

After about 7 months a Border Collie reaches about 90% of his size and after about 12 months he has reached about 90% of his final weight.

In numbers your Border Collie is between 43 cm and 50 cm tall at 7 months and weighs 26,5 – 40 lbs (12 – 18 kg). A female will usually rank at the lower end and a male at the upper end.

Remember that every dog grows at a different rate. The most important thing is that your Border Collie gains weight every week. Whether he weighs a little less than his brother in week 10 but makes up for it in week 12 is irrelevant.

How heavy is a Border Collie at 6 months?

It is not possible to give a relatively exact weight. The numbers only serve as a rough guide.

Generally speaking, a 6-month-old Border Collie should have reached about 60% of its full weight.

If we now assume that a male dog normally weighs between 14 and 20 kg, he is in the range of 8.5 kg to 12 kg at 6 months. But even here there can be deviations.

A female can reach a weight of 26,5 – 42 lbs (12 – 19 kg). So at 6 months, an intermediate weight of 15,5 – 26,5 lbs (7.5 kg to 11.5 kg) would be normal.

With this size the Border Collie is a great family dog.

Is your Border Collie particularly small and light? Or do you have an extremely large dog? Of course, extremes in body size also affect weight.

As a short example I can mention our Broholmer. We were at a breeding show. There was one female that was approved for breeding that was bigger than all the other female and even bigger or as big as most of the males.

The breeding judge, described her as an atypical female and the breeding requirement is that an atypical male (i.e. a rather smaller one) is mated to her to get typical puppies again.

So size and weight of dogs can differ significantly from the standard.

Weight table Border Collie

I did some research and was able to derive the following weight table as a guide.

AgeWheight MaleWheight Female
1 month3 – 6 lbs (1,5 – 2,5 kg)2 – 5 lbs (1 – 2 kg)
2 months6 – 11 lbs (3 – 5 kg) 6 – 9 lbs (3 – 4 kg)
3 months11 – 16 lbs (5 – 7 kg) 9 – 13 lbs (4 – 6 kg)
4 months13 – 18 lbs (6 – 8 kg)11 – 18 lbs (5 – 8 kg)
5 months16 – 22 lbs (7 – 10 kg)16 – 22 lbs (7 – 10 kg)
6 months22 – 28 lbs (10 -13 kg)20 – 16 lbs (9 – 12 kg)
7 months16 – 35 lbs (12 – 16 kg)22 – 30 lbs (10 – 14 kg)
8 months28 – 38 lbs (13 – 17 kg)24 – 33 lbs (11 – 15 kg)
9 months28 – 40 lbs (13 – 18 kg)27 – 35 lbs (12 – 16 kg)
10 months28 – 42 lbs (13 – 19 kg)27 – 38 lbs (12 – 17 kg)
11 months31 – 42 lbs (14 – 19 kg)28 – 40 lbs (13 – 18 kg)
12 months33 – 44 lbs (15 – 20 kg)31 – 44 lbs (14 – 20 kg)
2 months40 – 55 lbs (18 – 25 kg)31 – 44 lbs (14 – 20 kg)

The values can of course vary if your dog is particularly large or particularly small.

Border Collie female

  • The average female Border Collie weighs 9 – 13 lbs / 4 – 6 kg at 3 months of age.
  • The average female Border Collie weighs 20 – 16,5 lbs / 9 – 12 kg at 6 months of age.
  • The average female Border Collie has a weight of 30,8 – 44 lbs / 14 – 20 kg at 12 months.

Male Border Collie

  • The average male Border Collie has a weight of 11 – 15,5 lbs / 5 – 7 kg at 3 months of age.
  • The average male Border Collie has a weight of 22 – 28,5 lbs / 10 – 13 kg at 6 months of age.
  • The average Border Collie male at 12 months has a weight of 33 – 44 lbs / 15 -20 kg

Exceptions confirm the rule

On the Internet I also found the following data that prove that there can be significant fluctuations.

  • For example a 5 month old male with 53 cm and 33lbs / 15 kg.
  • Or a 1 year old male who is 60 cm tall and also weighs 50 lbs / 23 kg.
  • Another male I found who at 8 months had 46 lbs / 21 kg with 53 cm height at withers.

A female, had reached 26 lbs / 11.9 kg at 43 cm at 20 weeks (about 5 months) and 33,5 lbs / 15.5 kg and 48.8 cm at 8 months of age

You see, there can be outliers upwards, just as there are those downwards.

If you consider that in the second year still weight is added, because the dogs then become broader and get a stronger stature.

When is a Border Collie too fat?

A good indicator of whether your dog is too fat is the ribs. In an adult dog, you should be able to feel the ribs quite easily. If you can’t feel the ribs properly because they are under a layer of fat, your Border Collie is too fat.

With short haired dogs the rule of thumb is that you should feel the ribs but not see them.

With the Border, of course, this is less possible because of the long coat. But if you shear him in summer or he jumps into a lake, you can see the ribs if he is too thin.

Consequences if your Border Collie is too heavy

If your Border Collie is too heavy it can have health consequences. Especially with the very active dog breed overweight can have a negative effect on the joints.

If your dog is too fat, you should directly reduce the food ration a little bit and exercise your dog more.

It may also be that your dog has too little exercise. Read here how much exercise a Border Collie needs.

Feeding during growth

Since dogs grow relatively fast, it is better to let them grow a little slimmer in the first year. If your dog grows too big too fast, it can have negative effects on the joints and bones. The result can be HD and ED in old age.

Which food is the best

The dog is a carnivore and needs a food with a high meat content. Cheap food from the discount store is not recommended for several reasons.

On the one hand, they usually contain substances that have no place in dog food and on the other hand, the quality is not good.

Conclusion: How big and heavy will a Border Collie get?

At about 1.5 years of age, the Border Collie is fully grown and reaches approximately 48 – 56 cm and 31 – 44 lbs. The females usually remain somewhat smaller and lighter.

© Mikkel (Contributing image)


I am Marco and I have the pleasure of living with 3 large Mastiff-type dog breeds. I would like to share my dog-related experiences on this blog

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