Border Collie Growth Chart
Border Collies are intense herding dogs with a lean frame and fast metabolism. Most approach adult weight by 12–15 months. High activity can keep puppies looking slim while they still gain height and bone—track weight weekly for context.
Border Collie weight by age
Typical weight ranges based on Border Collie adult size and standard growth curves. Individual puppies may vary.
| Age | Expected weight (low–high) |
|---|---|
| 8 weeks | 4.2–12.8 lb |
| 12 weeks | 6.3–16.4 lb |
| 16 weeks | 8.2–19.5 lb |
| 20 weeks | 10–22.5 lb |
| 24 weeks | 11.6–25.2 lb |
| 32 weeks | 14.7–30.4 lb |
| 40 weeks | 17.7–35.3 lb |
| 1 year | 21.8–42.2 lb |
| 1y 26w | 24.8–45 lb |
Border Collie Growth Stages
Understanding the typical growth stages helps you know what to expect as your Border Collie puppy grows.
Neonatal
0–2 weeksPuppies are born with eyes and ears closed, relying entirely on their mother. Rapid weight gain occurs during this period.
Socialization
3–12 weeksEyes and ears open. Puppies begin to explore, play, and learn social behaviors. This is a critical period for development.
Juvenile
3–6 monthsRapid growth continues. Puppies become more independent, start teething, and develop coordination.
Adolescent
6–12 monthsGrowth rate begins to slow. Puppies reach sexual maturity and may test boundaries. Muscle mass develops.
Young Adult
12–15 monthsGrowth is nearly complete. Your puppy is filling out and approaching adult proportions.
Adult
15+ monthsYour puppy has reached their full adult size. Weight should remain relatively stable with proper nutrition.
Calculate Your Border Collie Puppy's Adult Weight
Enter your Border Collie puppy's age and current weight for an estimated adult weight range.
Enter your puppy's details to see the estimate
Border Collie FAQ
How much will my Border Collie puppy weigh as an adult?
A fully grown Border Collie typically falls between 27 and 45 lb. In this medium breed, males commonly reach 30–45 lb while females often land at 27–42 lb. Use this calculator with your puppy's age and current weight for a personalized estimate within those bounds.
At what age is a Border Collie fully grown?
Border Collies are medium dogs that typically reach most of their adult weight between 12 and 15 months. Border Collies often appear slim during intense adolescent activity periods. Slight muscle or coat fill may continue briefly after height stabilizes, so weekly weigh-ins give a clearer picture than a single reading.
How accurate is a Border Collie puppy weight chart?
Estimated Border Collie growth curves assume typical development, but intense herding metabolism create meaningful variation within the breed. Active pups may track below chart weight while still growing. Parent weight and body condition may refine predictions when available. Charts work best alongside sex-specific ranges and consistent measurement habits.