Border Collies are medium-sized dogs originating from the border between Scotland and England. They’re known for their intelligence, agility, and energy, making them excellent working dogs.
On average, Border Collies reach their maximum height and weight at 1.5 to 2 years old. Males tend to be somewhat larger than females, standing at 19 to 22 inches and weighing 30 to 55 pounds. Females stand 18 to 21 inches tall and weigh 27 to 42 pounds.
These growth rates can vary between individual Border Collies. Their nutrition, exercise, and genetics can influence their growth and development. Keep reading to learn exactly how big Border Collies can get.
Border Collie Breed Overview

The Border Collie is an intelligent and energetic breed, first bred to herd sheep. They are medium-sized dogs with a lean build and coats in various colors and patterns. Border Collies have high energy levels, a great work ethic, and an eagerness to please.
Border Collies are descendants of the Old Hemp, a sheepdog from England and Scotland. Old Hemp had exceptional herding abilities and worked as a stud to breed other sheepdogs. Other ancestors of this dog include the Bearded Collie, the Kelpie, and the Rough Collie.
As working dogs, Border Collies excel in agility, obedience, and herding trials. They thrive when given plenty of exercise and mental stimulation. So, they’re best suited for active owners who can give them plenty of opportunities to play.
In terms of temperament, Border Collies are friendly and loyal to their owners but can act reserved or even aloof around strangers. They’re good with children and other pets when socialized properly.
Their strong herding instincts can make them prone to certain behaviors. That includes nipping, chasing, and herding, which can become problematic if ignored. Proper training and socialization are essential for raising a well-behaved Border Collie.
Border Collie Size and Growth Chart
This growth chart is specific to Border Collies. It includes the height and weight of Border Collies at different stages of their growth. We’ve specified a general range for both height and weight, as the growth of each individual dog can vary.
Growth charts can be useful for owners to track the growth of their Border Collie and ensure they’re developing at a healthy rate.
Age | Male Height Range | Male Weight Range | Female Height Range | Female Weight Range |
1 month | 8 to 10 inches | 6 to 10 pounds | 8 to 10 inches | 6 to 10 pounds |
3 months | 14 to 16 inches | 15 to 20 pounds | 13 to 16 inches | 13 to 18 pounds |
6 months | 18 to 20 inches | 28 to 40 pounds | 17 to 19 inches | 23 to 35 pounds |
9 months | 19 to 22 inches | 36 to 50 pounds | 18 to 21 inches | 30 to 42 pounds |
1 year | 19 to 22 inches | 40 to 55 pounds | 18 to 21 inches | 30 to 50 pounds |
When Does a Border Collie Stop Growing?
Border Collies reach their full height and weight by 12 to 15 months. Although, their bone density and muscle mass may continue to develop for a few more months. Most Border Collies will stop growing in height by the time they reach their first birthday. In rare cases, they may grow a little more in height until they are 18 months old.
Individual Border Collies may have slightly different growth rates. So, they may continue to gain muscle mass and fill out until they’re almost 2 years old. But their height is usually fully developed when they’re 12 to 18 months old.
Tracking your Border Collie’s growth during its first year is crucial. Rapid or stunted growth can point to underlying health issues or nutritional deficiencies. Consult your vet if you have concerns about your Border Collie’s growth.

Factors Affecting the Size of a Border Collie
Border Collies can grow up to 22 inches tall, but some individual dogs may be bigger or smaller than others. Malnutrition, lack of exercise, and faulty genetics can prevent a Border Collie from reaching its potential.
Ideal Diet for Maintaining a Healthy Weight
The ideal diet for a Border Collie varies based on age, activity level, and body condition. Here are some general guidelines to help you create a balanced diet for your Border Collie:

How to Measure Your Border Collie
Measuring your dog during its growth period is important to ensure they’re developing normally. It can also help you watch their health and prevent obesity.
Here’s a step-by-step guide on how to measure your Border Collie:
If you have difficulty measuring your Border Collie, consult a vet for guidance.
Conclusion
Border Collies are a medium-sized breed known for their herding abilities and athleticism. Like all dogs, they go through a growth period during the first year with major changes in height and weight. Owners can use a growth chart to ensure their dog is growing at a healthy rate.
Factors like genetics, nutrition, and exercise can affect the size of a Border Collie. So, you must provide a balanced diet, regular exercise, and adequate mental stimulation.
Understanding how big Border Collies get and what factors affect their size is important for anyone wanting to own this breed. With proper care and attention, you can help them reach their maximum physical potential.
Featured Image Credit: Julia Suhareva, Shutterstock