Puppy Adult Weight Predictor
Predict your puppy's adult weight using current weight, age in weeks, and breed size maturity age.
Results
What is it?
The Puppy Adult Weight Predictor uses the common formula: Predicted Adult Weight = (Current Weight / Age in weeks) x Breed Maturity Age. It extrapolates current growth rate forward to the expected age of maturity for the breed size category.
How to use
Enter your puppy's current weight in kg, age in weeks, and select the breed size category. The larger the breed, the longer they take to reach maturity — large and giant breeds continue growing until 18-24 months.
Example scenario
A 16-week-old medium breed puppy weighing 5 kg: (5/16) x 36 = 11.25 kg predicted adult weight. The same puppy if it were a large breed: (5/16) x 26 = 8.1 kg — significantly less, reflecting that large breeds grow more quickly in the early weeks.
Pro tip
This formula is most accurate between 8-20 weeks of age. The best predictor of adult size is parent weights — if you know both parents, the puppy will typically fall between them. Toy breeds mature at 9-12 months, medium breeds at 12-15 months, large breeds at 18-24 months, and giant breeds may continue filling out until 3 years. Spaying/neutering timing can also affect final size.