Puppy weight calculator

We measured it rather than guessing. Using the same open dataset, we took puppies with an early weight and a later adult weight, projected forward from the early measurement, and compared the projection against what the dog actually weighed. That gives 579,135 prediction-versus-outcome pairs.

At 12 to 15 weeks the estimate lands within 23 percent below to 35 percent above the true adult weight for eight puppies in ten. By 46 to 60 weeks that tightens to 12 percent below and 18 percent above.

Anyone claiming better than that from a weight and an age is not measuring their own accuracy.

From 12 weeks the estimate becomes genuinely useful, and it keeps improving. Before 12 weeks our growth reference does not apply at all, so we say so rather than extrapolating off the end of the data.

Between roughly 16 and 26 weeks you get the best balance: accurate enough to plan around, and early enough for the answer to still be useful for choosing crate size, harness size, or an adult food.

It compares your puppy with healthy puppies of the same size category, sex, and age. The 60th centile means around 60 percent of healthy puppies weighed less at that age and 40 percent weighed more.

A high or low centile is not good or bad on its own. A puppy tracking steadily along the 20th centile is growing perfectly normally. What matters is the trajectory: a puppy dropping from the 75th to the 25th over a few weeks is worth a vet visit even though both numbers sit inside the healthy range.

Most of them use one linear formula: current weight divided by age in weeks, multiplied by 52. That assumes growth is a straight line. It is not. Puppy growth is an S-curve that is slow, then fast, then levels off, and the shape differs sharply by size.

At 16 weeks a toy puppy is already around half its adult weight while a very large puppy is only around two fifths of the way there. One formula cannot fit both. We use size-specific centile curves instead, and show you the linear answer alongside ours so you can see the gap.

Leave the size dropdown on "work it out for me". We infer the most likely size category from your puppy's weight and age, then project from there. No DNA test required.

Mixed breeds carry more uncertainty than purebreds because there is no breed standard to anchor against, so treat the range as genuinely important rather than decoration. Known parent weights can help select the category, but they do not bound the outcome.

No. The American Kennel Club publishes breed standards that include adult height and weight ranges, and it has published the popular linear rule of thumb, but it does not run a weight prediction calculator. We are not affiliated with or endorsed by the AKC.

Breed standards are still useful as a sanity check: if our estimate lands well outside the published range for your breed, the size category is probably wrong.

If you want to see what the rule the AKC popularised actually produces for your puppy, the AKC puppy weight calculator runs all three versions of it and shows the distance from a growth curve.

The research behind our growth reference looked at exactly this. Neutering before 37 weeks was associated with a slight upward shift in growth trajectory and neutering after 37 weeks with a slight downward shift, but both effects were small compared with the variation between individual dogs. The authors concluded separate curves for neutered dogs were not needed.

Neutering can affect body composition and appetite, which is a weight management question rather than a skeletal size question. That one is worth discussing with your vet.

Not on one measurement alone. Check the size category first, because choosing the wrong one is the single most common reason an estimate looks off.

What matters more than any single number is the direction of travel. A puppy that has always tracked the 90th centile is probably just a big puppy. A puppy that has climbed steeply across several centile lines in a short time is worth a conversation with your vet, who can assess body condition by feel in a way no calculator can.

It depends almost entirely on size. Toy and small breeds are essentially finished by 8 to 10 months. Medium breeds carry on to around 12 to 14 months. Large and giant breeds keep adding bone and muscle until 18 to 24 months, which is why the growth curves in this reference run all the way to two years.

Height finishes before weight. A large-breed dog usually reaches its adult shoulder height months before it fills out to its adult weight.

Not reliably. Large paws on a young puppy are a loose hint that there is more growing to come, but they are nothing like as informative as weight and age together. Some breeds are simply built with heavy feet.

Weight measured against age on a proper growth curve is far more predictive, which is what this calculator uses.

Weigh yourself, then weigh yourself holding the puppy, and subtract. Bathroom scales are accurate enough for this: a 100 gram error on a 5 kilogram puppy shifts the adult estimate by far less than the natural prediction range.

Weigh at roughly the same time of day and before a big meal, so you are comparing like with like over time.

Yes. Switch the unit toggle next to the weight field and every result, including the range and the reference tables, is shown in pounds. The underlying data is metric, so we convert at the boundary using the exact factor of 0.45359237 kilograms to the pound.

The growth reference is validated up to a predicted adult weight of 40 kilograms, which is about 88 pounds. Above that we tell you the estimate is beyond what the data supports rather than quietly reporting a number off the end of the curve.

Giant breeds also grow for longer than two years, so a dog in that range may still be filling out well after our reference stops.

Weekly until about 16 weeks, then every two to four weeks until growth flattens off. Plotting the same puppy repeatedly is far more informative than a single reading, because it shows the trajectory rather than a snapshot.

Take the numbers to your vet appointments. A growth curve over time is genuinely useful clinical information.

From the open dataset published alongside Salt and colleagues in PLOS ONE in 2017: roughly 15 million bodyweight records from Banfield Pet Hospitals in the United States, collected between 1994 and 2013 and released under a Creative Commons Attribution licence.

We derive our own reference from that data rather than reproducing the published WALTHAM charts, because the fitted parameters behind those charts were never published. Our full method is on the methodology page, and the derivation scripts ship with the site.