How accurate is the puppy weight estimator?

It uses common rule-of-thumb growth factors — accurate only for known pure breeds at typical ages. Crossbreeds, giant breeds and rescue puppies vary widely; ask your vet at vaccination visits.

At what age can you predict a puppy's adult weight?

Medium breeds: around 14–16 weeks (weight ≈ half adult). Large breeds keep growing longer. Before 12 weeks, estimates are especially unreliable.

Quick answer

The free PETHEALTH+ puppy weight estimator gives a rough adult weight band from your puppy's age in weeks and current weight. It uses common breeder/vet rules of thumb — mixed breeds and giant breeds need your vet's assessment, not an online guess.

Puppy adult weight estimator

A rough band for how big your puppy might grow — based on age, current weight and expected breed size. Mixed breeds and rescue puppies vary enormously — only your vet can give a reliable estimate.

Rule-of-thumb growth factors only — not a substitute for veterinary advice. See our puppy care guide and breed health hub.

Frequently Asked Questions

How accurate is the puppy weight estimator?: It uses common rule-of-thumb growth factors — accurate only for known pure breeds at typical ages. Crossbreeds, giant breeds and rescue puppies vary widely; ask your vet at vaccination visits.
At what age can you predict a puppy's adult weight?: Medium breeds: around 14–16 weeks (weight ≈ half adult). Large breeds keep growing longer. Before 12 weeks, estimates are especially unreliable.