Border Collie Weight Chart and Calculator

Border Collie Weight Chart (How much should your Collie weigh?)

Have you ever wondered what your Border Collie should weigh? What weight your Collie should be at six months? Well, we’ve kept a regular record of our Collies’ weight and used that data to create a variety of weight charts to help you understand the likely weight and growth of your Border. 

Understanding your Border Collies’ weight is an essential part of caring for your pup. If they’re too heavy, then it might mean that you’re over feeding them. If they’re too skinny then it may mean that they aren’t getting the nutrition that they need.

How much should my Border Collie weigh? 

This is a question almost every Border Collie owner will ask themselves at some point. In fact, Border Collies come in lots of different shapes and sizes. 

The main factors in determining what your Border Collie should weigh is both their gender and the size of their parents. Of course, it also matters what you feed them and how much exercise they get! 

The typical Border Collie weight is best expressed as a range for each stage of development. 

As a general guide, the following weights are regarded as typical for each age group: 

  • Eight weeks = 3-5kg (6-11 lbs) 
  • Six Months = 8-11 kg (17-24 lbs)
  • Twelve Months = 16-23 kg (35-50lbs)
  • Fully grown = 18-23kg (39-50 lbs) 

As you can see, Border Collie weight will increase rapidly in the first twelve months from just a few kilograms all the way up to 23 kilograms. It is for this reason, that it can be hard to work out whether your own Border Collie is at its own ideal weight. 

How do I calculate my Border Collie’s weight? 

Using the information that we recorded about our own Border Collie Mila, we created the following Border Collie weight calculator. While it is not going to be entirely accurate, it should help you to understand what your Collies’ weight is likely to be when they’re fully grown. 

Use the calculator below to find out what your Border Collies' fully grown weight might be.

What was the approximate weight of your Border Collie at 8 weeks?

Hint: 1 kg = 2.2 lbs

If you’d like to understand what your Border Collies’ weight is likely to be at different ages, you can use the weight chart we created below. All you need to do is to find the weight that is closest to the current weight of your own Border Collie, and trace the chart to find out the likely weight gain of your pup until it’s fully grown. 

Border Collie Weight Chart from 8 weeks to Fully Grown

How to tell if your Border Collie is the correct weight? 

Charts and data aside, only you and your family know the individual quirks of your own Border Collie. As a result, they may not quite follow a typical growth pattern, but this itself can leave many owners wondering whether their Collie is a good weight. 

The good news is that there is a very simple test that you can do when it comes to reassuring yourself that your Collie is of a healthy weight. 

The test itself is based on something called “Body Condition Scoring,” which is a fancy term that vets use to describe a dog’s appearance on a 1 to 9 scale. 

The test that vets use involves looking at a dog’s ribs, hips and waist, comparing what they can see and feel with picture guides and their own experience. If they give a low score, then a dog is overweight. If they give a high score then a dog is overweight. Just like goldilocks, something in the middle is about right. 

When it comes to reassuring yourself about your Collies’ weight, you can do a very simplified version of the same test by feeling your dog’s ribs. 

In short, if you can still feel their ribs with flat fingers and there’s still a layer of fat, then they are probably within a decent weight range. 

On the other hand, if you struggle to feel their ribs, that may mean they are slightly overweight, and if you can physically see their ribs then they are probably underweight. This may in turn have negative impacts on their life expectancy.

Of course, with all things to do with your dog’s health consult a vet if ever you are unsure or what a definite answer, but we do this little rib check from time-to-time to reassure ourselves that we’re not overfeeding our darling duo. A raw food diet can help you to get a little more control of what goes into your Border Collie!

Body Condition Score Chart for Border Collies

Border Collie weight increases over the months 

As I wrote above, we measured our Collie Mila’s weight over her first year as a puppy and used this information and the percentage increases to create the weight chart on this page. What’s really interesting to us is just how rapidly a Border Collie gains weight in the first few months. 

Hopefully, by reading the below, if your Border Collie doesn’t quite meet the weights in our chart above, you can calculate what your Collies’ weight is likely to be. 

2 months to 4 months:

Our own Collie, Mila weighed 4 kg at 2 months and 6.88 kg after 4 months. (Well, strictly speaking, she weighed 3.98, but we rounded up!) 

This is a weight gain of a huge 72% in just two months. What this means is that if you were to figure out your own Border Collies’ weight at 8 weeks, and multiplied it by 0.72, then you’re likely to get an estimate of what their weight will be at 4 months.

For example, if your Collie weighs, say, 6 lbs, you would multiply 6 by 0.72. This would give you a weight gain of 4.3 lbs. Adding that to their starting weight then gives you a 4 month weight prediction of 10.3 lbs. 

Border Collie Weight 4 months to 6 months:

Mila weighed 11.06 kg at 6 months of age. This means she increased her weight by 60% from her weight at 4 months. 

Again, if you were to use your own Collies’ known weight at 4 months and multiply it by 0.6 then you’ll arrive at a figure to add on to the starting weight and get your Collies’ likely weight at 6 months. 

Of course, this isn’t full-proof and so many factors will determine your own Border Collies’ weight (not least, whether you’re feeding them quality food). 

But, it should give you an indication of where they may end up. 

6 months to 1 year:

For almost every dog, the weight gain between 6 months to a year is probably the most noticeable for owners. This is because not only does their weight increase, but also their size. 

In our experience, this is the time period where your Collie will grow from being seen as a gangly puppy, to being seen as a proper dog (of course, they may not quite be acting like one at 12 months!).

In percentage terms, during this period Mila’s weight increased by 73%. 

What can we learn from this? Well, combined with their size increase, it will look like your Collie has properly “filled out,” even though they’ll still have a little more growing to do.  

Hopefully you’ve been reading along at this point and know the calculation to apply to get an estimate of your own Border Collies weight, but if not: 

(Your Collies’ weight at 6 months x 0.73) + Your Collies’ weight at 6 months = Estimated weight at 12 months. 

Why is weight important when neutering or spaying my Border Collie?

For medium and large dog breeds, the standard advice is that they should be close to, or have reached their adult body weight before they are spayed and neutered. For Border Collies, this means that your vet is likely to recommend that they are spayed or neutered closer to the 12 month mark than before. 

Border Collie females typically have their first season (or heat cycle) between 6 and 8 months, which means that vets are likely to recommend spaying after this point as many regard it as healthier for your dog. 

That said, there is lots of conflicting advice when it comes to the exact point you should spay or neuter your dog. The best thing to do when considering this option is to speak with a vet you trust and seek their advice about the best course of action for your individual pooch. 

When it comes to Border Collie weight, then, while it is certainly a factor in deciding the appropriate point to spay or neuter, it’s not the only factor.

Interested in learning more about caring for your Collie, why not check out our article about how to bath a Border Collie. Or, if you prefer, a detailed (but friendly) guide to caring for your Border Collie’s teeth.

Also recommended – what fruits are safe for Border Collies to eat (apples, pears, pinapple … etc.)

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Top picks for our Border Collies


Ok, it’s a bold statement, but I think that this interactive dog puzzle toy is absolutely brilliant! 


We all know Collie’s love to be … challenging! Give them this snuffle mat and you’ll get at least 10 minutes peace!


We’ve tried absolutely loads of different types of shampoos and dog conditioners. Save yourself some time and try our favourite brand – works a treat!