Puppy Growth & Adult Weight Predictor
Predict how big your puppy will grow.
Wondering how big your puppy will get? The most reliable predictor is current weight at a known age, scaled by the dog's breed size category. This calculator predicts adult weight to within ±15% — useful for planning crate, harness and food budget.
How this calculator works
The calculator uses the standard (current weight × age factor) formula tuned to each size category. Toy and small breeds finish growing around 9–12 months; medium dogs at 12–15 months; large and giant breeds keep growing until 18–24 months.
Frequently asked questions
How accurate is the prediction?
Within ±15% for most breeds when age is between 8 and 24 weeks. Predictions before 8 weeks or for unusual mixes can vary more.
When should I switch from puppy to adult food?
Toy/small breeds at 9–12 months, medium at 12 months, large/giant at 18 months. Switching too early on a giant breed can cause skeletal issues.
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