Puppy Weight Calculator

This puppy weight calculator allows you to estimate how big your dog will be when it grows up. Enter the current weight and age of the puppy as well as its expected adult size to get an estimation of its likely final weight.

This is possible because puppy growth generally follows a relatively predictable course. At certain ages, a puppy will typically have reached a known percentage of its final adult weight, with that percentage being largely dependent on how large the breed becomes as an adult. By inverting this relationship, one can calculate what their expected adult weight would be based on their current weight.

How to use the calculator:

Weigh the puppy and note its age. If the puppy can't hold still, pick it up and weigh yourself with the puppy then subtract your own weight.

Select the appropriate category for expected adult size based on dog breed or parent dog's size. If mixed breed and hard to decide, select the larger of the two parents or start with medium. After entering information, predicted values, possible ranges, and growth curve will be updated.

Method based on growth curve.

An accurate method of predicting an adult dog's weight is to use percentages relative to the expected final weight. As puppies in certain size categories reach a particular percentage of their eventual weight as they age, it is possible to calculate the likely weight of an adult dog by dividing its current weight by the corresponding percentage of the expected final weight.

As small dogs mature faster than large dogs, toy breeds will reach the appropriate percentage of their adult weight earlier than very large dogs. For this reason both size category and the figure on the scales are important.

Example calculation:

Let's say a puppy weighs 10 pounds and is currently 12 weeks old. A medium-sized puppy at about 2.8 months of age has already reached approximately 44% of its eventual weight.

So the calculator will predict an adult dog weight of around 22 to 23 pounds, with a likely range of about 18 to 27 pounds, given normal individual variation.

Percentages of expected final weight by age and size.

These are the growth rates used in the calculators and were obtained from extensive growth studies by veterinarians. If you follow down the "body type category" column, you can see what percentage of an adult dog's expected weight a puppy of that category will reach at each age.

The formula for one year and why its accuracy falls away:

Rules for quickly estimating an adult dog's weight are often found.

A 9 pound puppy that is 12 weeks old would be expected to weigh 39 pounds using this method, and the calculator will show this as a rough estimate.

However, growth is not linear. Puppies grow rapidly during the first few months and then gradually slow their rate of growth. Therefore, the one year formula tends to overestimate the weight of puppies, large dogs, and giant breeds that may continue growing for many weeks beyond 52 weeks. A method based on growth curves might be more appropriate in such cases.

Breed type categories for adult dogs.

The body type categories are crucial as they determine the entire growth curve. It is therefore important to select them as accurately as possible. Below you will find some representative dog breeds for each category, based on the weight ranges of adult dogs used in the calculator tool.

General rules according to body type:

Breeders follow a few simple methods that are in line with the growth curve and can be used to check if the values shown by the calculator make sense.

Factors that affect a puppy's adult body structure are:

Race and genetics play a major role. This is why the body type category has the biggest influence in the calculator. There are also other factors that can slightly alter your final weight.

Gender also plays a role; males are generally heavier than females of the same breed, usually by about 5 to 15 percent, with this difference being most pronounced in large and very large dogs.

The effects of nutrition on health are greater than the ultimate effect on body weight. Overfeeding large breed puppies accelerates growth and increases the risk of problems with joints and skeleton. The goal should be to maintain steady growth and a healthy body shape, not rapid gain in size.

Castration or sterilization at too early an age can delay the closure of growth plates and cause dogs to tend to be a little taller rather than heavier, but the effect on final weight is small.

When does a puppy stop growing?

Height stabilizes before weight does. Dogs first reach their full height and then gradually develop muscle and a strong skeleton. Small breeds finish growing earlier in all areas.

How accurate are predictions?

With purebred puppies with well-defined body type categories, the prediction results are usually within about 10 to 15 percent above or below actual adult weight. The older the puppy gets and the shorter the remaining growth period is, the more accurate the predictions become. For small dog breeds, months 4-6 are most predictive while for large dog breeds, months 6-9 are best.

For mixed breed dogs and very large dog breeds the differences are bigger so the calculator will show a range of values instead of an individual number. If your puppy is deviating significantly from the predicted curve or losing weight you should consult with your vet.

Symbols used:

This calculator provides a general estimate and is only meant to be used as a reference for interest or planning purposes. It is not veterinary advice. If you have any concerns about your puppy's growth, weight, or health, please consult with a veterinarian.