ForTheBreed

Puppy Weight Calculator

Wondering how big your dog will get? Look up the adult weight by breed, or estimate it from your puppy's current weight and age. Results in kg and lbs.

In short: the best predictor of adult size is the breed's typical weight range. As a rough rule, a puppy reaches about half its adult weight roughly a third of the way through growth, and is fully grown by around 12 months (small), 18 months (large) or 24 months (giant).

A Afghan Hound typically grows to

23 to 27 kg

(51 to 60 lbs)

Most large breeds are fully grown by around 18 months.

How to predict a puppy's adult weight

There is no perfect formula, because two puppies from the same litter can end up different sizes. What works well is to start from the breed. Decades of breeding have made adult weight fairly predictable: a Cocker Spaniel settles around 12 to 15 kg, a Labrador around 25 to 36 kg, and a Great Dane well over 50 kg. If you know the breed, the adult range is your answer, and our breed lookup gives it instantly.

When the breed is unknown, or you have a crossbreed, the next best method is the growth fraction. Puppies grow on a curve that is steep early and flattens as they mature. By weighing your puppy and knowing roughly how far through that curve it is, you can divide the current weight by the fraction of growth already reached. Our estimator does this for you: enter the current weight, the age in months and the expected size, and it returns an adult figure in both kilograms and pounds.

When are dogs fully grown?

Growth timelines differ sharply by size, and this is the single biggest reason a one-size formula fails. Smaller dogs reach their full frame quickly, while giant breeds keep growing for up to two years. Using the right maturity age matters: estimate a giant-breed puppy as if it were small and you will badly underestimate the adult weight.

  • Small breeds: fully grown by about 12 months.
  • Medium breeds: around 14 months.
  • Large breeds: roughly 18 months.
  • Giant breeds: can keep developing until 24 months.

Whatever the calculator says, weigh your dog at routine vet visits and watch the trend rather than a single reading. A puppy that is tracking steadily along a healthy curve is doing well, and your vet can flag if growth looks too fast or too slow.

Frequently asked questions

How big will my puppy get?

The most reliable guide is the breed's typical adult weight range. If you do not know the breed, you can estimate from current weight: a puppy roughly halfway through its growth window has reached about half of its adult weight, so doubling at that point gives a rough adult figure.

At what age is a dog fully grown?

It depends on size. Small breeds usually finish growing by about 12 months, medium breeds by 14, large breeds by 18, and giant breeds such as Great Danes can keep filling out until 24 months.

Can you predict adult weight from paw size?

Paw size is only a loose hint. Big paws on a young puppy suggest more growth to come, but breed and parent size are far better predictors. Our calculator uses growth fractions by size rather than paw measurements.

Why is my puppy bigger or smaller than the estimate?

Individual dogs vary with genetics, diet, neutering age and sex, with males often heavier than females. The breed range and growth estimate are guides, not guarantees. Weigh at vet visits and track the trend.

Want the full picture on a breed? Browse our breed guides for adult weight, lifespan, temperament and UK costs, or work out portions with the dog food calculator.