Tools you might need next
Calculate daily pet food portion size from body weight, age, and activity level. Estimate cups or grams for dogs and cats on dry or wet food.
Calculate recommended daily exercise minutes for dogs by breed size, age, and energy level. Plan walks, runs, and play for healthy activity.
Calculate pet medication dose from body weight and drug concentration. Convert mg/kg prescriptions to tablet or liquid volumes for dogs and cats.
Small breeds reach adult weight by 10–12 months; medium by 12–15 months; large by 15–18 months; giant by 18–24 months. Growth percentage at a given age varies by size class.
Adult weight ≈ Current weight / Age fraction of maturityFor puppies under 16 weeks in medium breeds, a simplified estimate: weight at 14 weeks × 2.5 approximates adult weight. Adjust multiplier by size class (small: 2.0; giant: 3.5+).
Adult ≈ Weight at 14 weeks × Size multiplierGrowth is not linear — rapid early gain slows after 6 months in large breeds. Use size-specific curves rather than simple extrapolation from a single data point after 6 months.
Adult ≈ Current weight / (% mature weight at current age)Updated: July 2026
At 14 weeks a medium breed is roughly 40% of adult weight. Estimated adult: 10 / 0.40 ≈ 25 kg (55 lb). Monitor monthly and adjust as growth curve progresses.
Large breeds at 6 months are approximately 60–65% of adult weight. Predicted adult: 25 / 0.62 ≈ 40 kg. Growth plates may still be open — avoid overfeeding for size.
Small breeds at 4 months are ~50% of adult size. Predicted adult ≈ 5 kg (11 lb). Small breeds complete growth earlier — confirm by 10 months.
Large and giant breeds mature slower and reach a lower percentage of adult weight at the same age. Applying small-breed multipliers overestimates adult size dramatically.
Neonatal and very young puppy weights are poor predictors due to litter size effects and early growth spurts. Wait until 12–16 weeks for more reliable medium-breed estimates.
Puppy weight at a given age correlates with adult size, but growth rates differ by breed category. Small breeds mature faster than giant breeds. This calculator estimates adult weight from current age and weight using size-class growth multipliers.