Puppy Adult Weight Predictor
Estimate a puppy's adult weight from its current weight and age.
Rough estimate — accurate to about ±15%. Parent weights are usually a better predictor if you know them.
Puppy setup essentials
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About this tool
Small-breed dogs (under 22 lb adult) reach full size by 9-12 months. Medium dogs (22-55 lb) by 12-15 months. Large dogs (55-100 lb) by 15-18 months. Giant breeds (over 100 lb) by 18-24 months. Using a growth curve for the size category, current weight, and age, you can project the adult weight within roughly ±15%.
Formula & notes
Uses the standard multiplier method: current weight × (adult age / current age) × size-adjusted factor. Small breeds double from 4 months to adult; medium roughly 2.5×; large roughly 3-4× depending on breed. If you know the parent weight, the average of both parents is often more accurate than any formula. Not applicable to mixed-breed puppies of unknown parentage — use conservative estimates in that case.
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