How To Tell How Big A Mixed Puppy Will Get

Puppies are adorable and easy to fall in love with, and that’s why most people choose to adopt puppies rather than adult dogs. Mixed puppies will usually have parents of different breeds, leading to a combination of genes for the puppy. It can, therefore, be a challenge estimating just how big the puppy will get as an adult. It is important to know how big a dog will get because bigger dogs require larger living spaces as opposed to smaller dogs.

Here are the most accurate methods you can use to determine how big your mixed puppy will get.

Get Information About the Mixed Puppy’s Parents

It is always prudent to get as much information as you can about a mixed puppy’s parents. Reputable breeders will always have this information on hand so you can always ask for the details. Even when you can’t get information on both parents, if you meet the puppy’s mother, you will have a good indication of the physical characteristics to expect.

Female mixed puppies will usually grow to be almost the same size as their mother while male mixed puppies tend to be larger than females and will likely be bigger than their mothers once they mature.

Check the Mixed Puppy’s Coat

Most breeds have distinct coat characteristics that are unique to their breed. If you are adopting a puppy of unknown parentage, you can ask a veterinarian if they can tell the parentage of the puppy based on their coat. Some dog shelter attendants are also quite experienced in terms of dog breeds and may be able to tell you the breed. Once you have information on the likely breed, you can then find out how big those breeds usually get.

Have a Vet Examine Your Puppy

Vets come across all types of pure breeds and mutts in their line of work. They are therefore quite knowledgeable on most breeds and will often be able to estimate just how big your puppy will be once it reaches adulthood.

Use Height, Weight, and Age

You can use your mixed puppy’s weight and age to approximate the likely adult size.

  • Mixed dogs below 20 pounds are small breed dogs.
  • Mixed puppies between 20 – 60 pounds are medium breed dogs.
  • Mixed puppies between 65 – 120 pounds are large breed dogs.

Mixed puppies are considered puppies until the age of 1. However, small breed mutts will be fully grown by 6 months while the larger breeds will be fully grown by 14 months.

Use Puppy Weight and Height Calculator

A general formula used to estimate a mixed puppy’s expected size is to multiply your puppy’s weight at four months by 4. For large breeds, the weight of the adult dog is usually double its weight at six months.

Alternatively, you can calculate how much weight the puppy gains each week and then multiply it by 52. This formula is based on the fact that most puppies will reach their full size at the age of 1, which is 52 weeks old.

Study Your Puppy’s Paw Size

The bigger the size of your puppy’s paw, the bigger they are likely to be in adulthood. Large breed dogs will tend to have large paws as puppies. A small paw will be approximately 2 inches or less, while 2-3 inches is considered medium-sized paws. If your mixed puppy has paws larger than 3 inches, they are likely to grow into a large-sized dog.

Check Your Mixed Puppy’s Skin

Saggy and loose skin is an indication that your mixed puppy is likely to grow into a large dog. Larger breeds tend to have loose and saggy skin as puppies which gradually fills out as they grow into adulthood. In most cases, puppies with loose and saggy skin will also have wrinkly faces so this particular characteristic is easy to pick up on.

Examine Your Puppy’s Bone Structure

A large frame with heavy, strong legs and large paws is a fairly good indicator that your mixed puppy will likely grow into a large-sized adult dog. Small breeds tend to have short limbs with small paws and a small body frame. You can use this to get an idea of just how big your mixed puppy is likely to get as an adult.


The potential size of a dog is an important factor to consider before you bring a mixed puppy into your home. Always try to find out as much as you can about the puppy’s physical characteristics to make sure it will fit into your home and lifestyle.

Many people end up with a dog they are not fully prepared for because they do not know what to expect when they adopt a mixed breed puppy. For example, if you live in a small apartment, the limited space might be too cramped for a large dog, so smaller breeds are a better option. Ultimately making an informed choice is better for both you and the dog.


Hello, I'm Shelly! I write about all things dogs. I'm a proud mother of 3. So I guess my official title is fulltime mother, part-time dog blogger. Look around and if you have any questions reach out to me