How big will my puppy get?

Enter your puppy's weight and age in weeks. The calculator compares it with typical growth curves for each size of dog and estimates adult weight.

Works from 8 weeks old.
?lb as an adult (estimate)

Growth analysis

Likely range
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Growth curve used
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Grown so far
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Usually done growing
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Growth varies a lot between puppies and breeds. The parents' adult weights are often the best guide you have.

How the estimate works

Small breeds grow fast and finish early, while giant breeds grow for up to two years. Research on puppies of different breeds shows how much of their adult weight they've usually reached at each age. The calculator divides your puppy's weight by that share. If you choose "Not sure", it picks the size curve that matches the result.

How accurate is it?

Treat it as a rough guide with about a 15% range either way. Mixed breeds, diet and neutering age all shift the curve. Estimates get better as your puppy gets older, so check again every month.

Use it for feeding and gear, not judgement

Large and giant breed puppies should eat a food made for large-breed growth, since growing too fast is linked to joint problems. The estimate also helps with crate and harness sizes.

Questions

At what age is a puppy half its adult weight?

Roughly 14-16 weeks for small breeds, 4-5 months for medium breeds, 5-6 months for large breeds and 6-7 months for giant breeds.

Do paw size or the "double at 16 weeks" rule work?

They are rough rules of thumb. A size-specific growth curve or the parents' weights are usually better guides.

Sources
  1. Hawthorne et al., Body-Weight Changes During Growth of Puppies of Different Breeds (Purdue Center for Animal Welfare Science summary)

Last reviewed October 20, 2026. Estimates for healthy pets only, not veterinary advice.