Predict your puppy's adult weight based on breed-specific growth curves
Predicting how big your puppy will get starts with understanding their breed's size category. Dogs are grouped into five categories: toy, small, medium, large, and giant. Each category follows a different growth trajectory based on extensive veterinary research.
Our predictor uses growth milestone data from Salt et al. (2017), published in Veterinary Record. This study tracked how dogs of different sizes gain weight over time, establishing percentage-based milestones at each month of age.
The methodology works in three steps:
For example, a 4-month-old Labrador (large breed) that weighs 15 kg has reached approximately 41% of adult weight. Dividing 15 by 0.41 gives a predicted adult weight of about 36.6 kg (80.7 lb).
Puppies don't grow at a constant rate. Their development follows distinct phases, and the timing varies significantly by size category:
Puppies gain weight quickly, reaching 36–47% of adult weight by 3 months. Toy breeds develop fastest during this phase.
Growth continues at a strong pace. By 6 months, most puppies have reached 67–80% of adult weight. Small breeds may already be at 78%.
Weight gain decelerates. Toy and small breeds approach adult weight by 9–12 months, while giant breeds still have significant growth ahead.
Large and giant breeds continue filling out. Giant breeds may not reach full adult weight until 18–24 months. Most other categories plateau by 12 months.
The key difference between size categories is maturity speed. Small breeds mature faster than giant breeds. A Chihuahua may be fully grown by 9 months, while a Great Dane continues developing until age 2.
The age at which a dog reaches full adult weight depends on their size category:
| Size Category | Adult Weight Range | Growth Complete |
|---|---|---|
| Toy | 3.3–11 lb (1.5–5 kg) | 9–12 months |
| Small | 11–22 lb (5–10 kg) | 9–12 months |
| Medium | 22–55 lb (10–25 kg) | 12–15 months |
| Large | 55–99 lb (25–45 kg) | 15–18 months |
| Giant | 99–198 lb (45–90 kg) | 18–24 months |
Track your puppy's weight weekly with a precision pet scale. The Greater Goods pet scale offers 0.1 oz / 1 g accuracy.
View on Amazon →Keep treats under 10% of daily calories during training. These low-cal options help maintain a healthy weight.
View on Amazon →This tool provides estimates based on published growth data (Salt et al., 2017, Veterinary Record). Individual dogs vary based on genetics, nutrition, and health. Always consult your veterinarian for personalized advice about your puppy's development.