Puppy size · adult weight

How big will my puppy get?

Put your puppy’s age, current weight and rough size in below and this calculator estimates how big it will grow — using the method vets and breeders use (how much of its adult weight it has already reached for its size), not the “double it at four months” shortcut, which only works for medium dogs. Pick a breed and you’ll also get that breed’s own adult range, the surest guide of all.

Yellow Labrador Retriever standing outdoors
Photo: Skansken — CC BY 3.0, via Wikimedia Commons
Full-grown, your puppy will weigh about
30lb
50% grown likely 25–34 lb

Estimates from a puppy under three months old are rough — the younger the puppy, the wider the real range. It firms up after about six months.

How we work it out (and why “double it at four months” isn’t enough)

A puppy doesn’t grow at a steady rate, and it doesn’t reach the same share of its adult size at the same age as every other puppy. A toy breed is already about two-thirds of its grown weight at four months; a giant breed is only about a third of the way there and will keep growing for another year and a half. So the trick is to ask what fraction of its adult weight a puppy of this size has reached at this age, then divide: adult weight ≈ current weight ÷ that fraction.

The per-size growth curves here are calibrated to the widely published half-grown milestones and maturity ages, and the peer-reviewed backing is Salt et al. (2017), whose growth standard charts were built from more than eight million vet weight records. The full curve is in the chart below — nothing hidden. Because real growth varies with genetics, nutrition and health, the answer is shown as a range, not a single false-precise number, and it firms up after about six months of age.

The “big paws mean a big dog” rule

It’s a fun one to believe, but paw size is a weak clue at best — some pups just have big feet for a while. Your puppy’s weight-for-age against its size class, or its breed’s adult range, tells you far more.

The five size classes

Roughly how big each grows and when it finishes — pick the one your puppy will most likely land in, or choose a breed to set it automatically.

Toy

under 11 lb · under 5 kg

Half-grown at about 3 months; full-grown by 9–10 months.

Small

11–24 lb · 5–11 kg

Half-grown at about 3 months; full-grown by 10–12 months.

Medium

24–55 lb · 11–25 kg

Half-grown at about 4 months; full-grown by 12–14 months.

Large

55–88 lb · 25–40 kg

Half-grown at 4½–5 months; full-grown by 15–18 months.

Giant

over 88 lb · over 40 kg

Half-grown at 5–6 months; full-grown by 18–24 months.

How much of its adult weight a puppy has by each age

The exact curve this calculator runs, as a percentage of grown weight, by size. This is why the same age means a different “% grown” for a toy and a giant.

Puppy’s ageToySmallMediumLargeGiant
2 months38%34%27%23%19%
3 months52%50%39%34%28%
4 months65%60%50%44%37%
6 months82%78%68%60%50%
9 months96%93%87%80%68%
12 months100%100%98%92%82%
18 months100%100%100%100%95%

Percentages are the growth-curve anchors, interpolated between; real puppies vary by roughly 10–20%. Giant (>40 kg) breeds are the least certain of all.

Find your puppy’s breed

Pick a breed to load its size and see its published adult weight range — for a known breed that range is a surer guide than any formula. Or open its full profile.

BeagleBoxerChihuahuaChippiparaiCocker SpanielDachshundDoberman PinscherGaddi KuttaGerman ShepherdGolden RetrieverGreat DaneIndian Pariah DogKombaiLabrador RetrieverMudhol HoundPomeranianPugRajapalayamRampur GreyhoundRottweilerShih TzuSiberian Husky

Common questions

How big will my puppy get?

The honest method is to work backwards from how much of its adult weight a puppy has already reached: adult weight ≈ current weight ÷ that fraction. A medium puppy is about half its adult weight at four months, so a 15 lb four-month-old medium pup lands near 30 lb grown. Enter your puppy’s age, weight and size above for its own estimate — and for a known breed, the breed’s published adult range is the surest guide of all.

Is “double the weight at 16 weeks” accurate?

Only roughly, and only for medium dogs. How much of its adult size a puppy has reached at 16 weeks depends on how big it will get: a toy breed is already about two-thirds grown at that age, while a giant breed is barely a third of the way there. Doubling works for a medium dog and over- or under-shoots for the rest, which is why this calculator uses a per-size growth curve instead.

Do big paws mean a big dog?

Not reliably — it’s an old wives’ tale. Some big-boned pups have paws that look oversized for a while and some don’t; paw size is a hint at best. Your puppy’s age-and-weight against its size class, or its breed’s adult range, tells you far more than its feet do.

When will my puppy stop growing?

It depends on size. Toy and small dogs are usually full-grown by 9–12 months, medium dogs by about 12–14 months, large dogs by 15–18 months, and giant breeds keep filling out until 18–24 months. Big dogs grow for longer, which is also why their early estimates are the least certain.

How accurate is a puppy weight calculator?

Treat it as a good estimate, not a promise — real adult weight varies by roughly 10–20% with genetics, nutrition and health, and the estimate firms up after about six months of age. For a mixed breed the parents’ sizes are the strongest clue. For anything health- or diet-related, your vet, who can weigh and examine the actual puppy, is the real authority.

Where these figures come from

This calculator is a guide, not veterinary advice. Every dog is an individual — for anything about your puppy’s growth, diet or health, ask your vet, who can weigh and examine the actual dog.