How to Tell How Big a Mixed Puppy Will Get (various methods)

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small mixed breed pup

While purebred pups often get all of the attention, mixed breeds deserve a lot of love, too! Mixed puppies can be a joy to raise. Unlike purebreds dogs, you never know what you’re going to get.

These pups can take on traits from both of their parents, resulting in a one-of-a-kind canine companion. This doesn’t apply to just personality. Their physical appearance can be unique as well.

With all that said, there is one issue that owners of mixed puppies have to prepare for.

With mixed breeds, it’s not easy to tell how big a puppy is going to get.

There are no set standards involved, leaving a lot to the unknown. Luckily, there are some ways to get a better idea of what you expect in the future as your puppy grows into a happy and healthy adult.

What Are Mixed-Breed Puppies?

Also known as a Mutt or Mongrel, mixed-breed pups are canines born from parents of two different breeds.

Canines are capable of cross-breeding, resulting in distinct dogs with characteristics that don’t fall under one specific breed.

Cross-breeding is relatively common. Not only does it happen naturally when dogs are in heat, but some of the most popular breeds we know today were a byproduct of cross-breeding!

There’s a common misconception that mixed breeds are somehow inferior to purebreds. That’s simply not the case!

Mixed breeds have their own unique challenges. But, the cool thing about these pups is that they are less likely to suffer from genetic defects or inherited health problems.

When a new puppy is born, the strongest genes prevail. This can result in some out-of-this-world traits. Take a look at the Labradoodle or Pomsky!

Mixed puppies are great for dog owners of any skill level. They make excellent companions and are very trainable.

There are no guaranteed issues that will affect your pup’s health and well-being just because they are a mixed breed.

The only problem you will have to deal with is planning for their adult size!

Understanding the Growth Cycle

Before you try to figure out how big your mixed furry friend will get as an adult, you need to understand the growth cycle.

Another big misconception out there is that puppies reach adulthood at a specific age. Some will say it’s after a year while others say it takes a couple of years of growth.

Truth is, it’s different for every dog. Puppies can take anywhere from 6 months to 2 full years to reach maturity.

Typically, smaller dog breeds will mature faster than large ones. This is important, as you can use established growth stages to get a better idea of where your dog will lie in that size spectrum.

In total, there are five identifiable puppy growth stages you can look out for.

Neonatal Stage

The first stage begins immediately after birth and can last up to two weeks depending on the breed of the parents. At this point, your puppy is very vulnerable. They can’t see or hear just yet, so they rely on the guidance and protection of their mother.

Transitional Stage

After the neonatal stage, your new companion will start acting like an energetic puppy! Their eyes will open and they are finally able to start walking around.

You can usually observe signature puppy-like behaviors, such as playing, wagging their tail, and more. Generally, this period can last up to 4 weeks of age.

Socialization Stage

This is one of the most crucial stages in your puppy’s growth cycle. It’s when they need to be exposed to as many people and dogs as possible! It’s theorized that the things puppies learn during this stage will affect their temperament and behavior as an adult.

Take this opportunity to play with your new pup and make them comfortable with the world.

Bring them to meet your family, expose them to any other dogs you have in the home, and spend lots of time with them. Failure to do all that could result in an adult dog that’s shy, anxious, and aggressive.

Ranking Stage

Between 3 and 6 months of age, your pup will go through a number of physical and mental changes. On the physical front, puppies typically start teething at this stage.

They can be a bit irritable as their teeth break through the gums. You will have to deal with excessive chewing and some destruction.

Mentally, this is when puppies learn about the social order or canine packs. They begin to understand dominance and submission. Thus, it’s a great time to start training.


The adolescent stage is the one that lasts the longest. It lasts from 6 months until your dog fully matures.

Your pup will be a playful little creature exploring their surroundings and learning about the world. They’ll also begin to learn their place in your family and develop a strong bond with you.

Different Size Classifications

Now that you understand how puppies grow, what are the size classifications of adult dogs? This can be a bit confusing for many people. There tends to be a lot of overlap when different breeds are discussed.

With that said, there are some distinct weight differences between these classes. The different size classifications will affect how your dog grows up and their needs moving forward.

Small Breeds

Any adult dog that weighs less than 20 pounds is considered to be a small breed. Think Chihuahuas, Dachshunds, and Shi Tzus.

Medium-Sized Breeds

Dogs that weigh between 20 and 60 pounds are medium-sized. This is a relatively wide range, so it’s important to stick to the numbers when classifying your dog.

Medium-sized dog breeds include Shibu Inus, Collies, and even Siberian Huskies.

Large Breeds

If dogs weigh 65 to 120 pounds, they are large breeds. Some example breeds include Alaskan Malamutes and Rottweilers.

Giant Breeds

Finally, there are giant breeds. These are dogs that tip the scales over 120 pounds. Some of the most popular giant breeds include Great Danes, Newfoundlands, and St. Bernards.

Methods to Determine A Mixed Puppy’s Adult Size

There are several ways to tell how big a mixed puppy will get. They’re not always an exact science, but these methods will give you a good idea of what to expect.

Take a Look at Their Parents

The best way to see how big your pup will get? Meet their parents!

Like we mentioned earlier, mixed puppies take on traits from both of their parent breeds. So, your pup isn’t going to get any bigger than the mother and father.

Pay close attention to the mother’s size. She is a good representation of what your puppy will grow up to be. Females tend to stay relatively close to their mother’s weight and size.

Meanwhile, males can get a bit bigger. Though, it’s not by much.

Analyze Their Paws

While your pooch’s paws will grow a bit as they get older, they are a great indicator of how big they will be.

The paws are a part of the body that dogs rely on from birth. As such, they’re pretty developed early on.

A puppy who is destined to be a large dog isn’t going to have dainty little paws. So, you can use this as a sign to better gauge their adult size.

Lay your dog’s paw on a piece of paper and measure it from top to bottom. If possible, consider making a paw print for easy reference. Now use that measurement to see how their paws compare.

  • Small dogs: 2 and a half inches or less
  • Medium-sized dogs: Approximately 3 inches
  • Large dogs: Up to 4 inches
  • Giant dogs: Larger than 4 inches

Examine Their Coat

Sometimes, the quality of the coat can provide you with plenty of information.

A puppy’s coat will develop over time, so you will need to wait several months before you can start making comparisons to certain breeds.

Analyze the color and texture of the fur. You can use this narrow down possible parent breeds.

It’s also a good idea to consult with your vet. Veterinarians spend all day around canines of all breeds. They may be able to identify the fur patterns and provide you with information from there.

Bone Structure and Body Condition

As long as you’re feeding your puppy a healthy diet, you should be able to look to their bone structure and body condition for clues.

Diet has a huge effect on how a puppy grows up, so we recommend consulting with your vet regularly to ensure that they are getting all the nutrition they need.

As a good rule of thumb, you should be able to see your dog’s waist from above without seeing visible ribs. This is a good indicator that your pup is on the right track.

Now, onto the bone structure.

Take a look at your dog’s legs and paws. In most cases, thick bones and meaty paws indicate that your pup is destined to be quite large.

The opposite applies to smaller dogs, who have thinner legs.

There are some outliers to this rule, such as Greyhounds. So, don’t rely on this method alone.

Do the Math

The last technique is to do some math. If you’re weighing your new pup on a regular basis, you can use those figures is a few different ways.

While it’s not always perfect, the following equations can be quite useful for monitoring your pup’s health and planning for the future.

Using Weekly Growth

The first equation is best for small and medium-sized dogs that reach adulthood in about a year. Weigh your pup to get their current weight. Then, divide that figure by their age.

Say, for example, that you have a 20-pound pup who is 16 weeks old.

You would divide 16 by 20 to get 0.8. Your puppy has gained approximately 0.8 pounds each week. Now, multiply that by 52. This is the estimated weight of your pup at a year old.

Size Classification Equations

There are some equations that breeders have come up with to determine a puppy’s adult size at various stages. To use these equations, you need to have a general idea of what size classification they belong to.

You can figure this out using the other techniques or taking a look at their parents.

For small dogs, take their weight at 16 weeks old and multiply it by 4. This will be a rough estimate of their weight at full maturity.

For medium-sized dogs, take their weight as 14 weeks old and multiple it by 2.5 to get their estimated adult weight.

To figure out the adult weight of large and giant breeds, record their weight at 16 weeks old and multiply it by 2.


It’s impossible to know for sure how big your dog will get as an adult. This doesn’t just apply to mixed-breeds. There’s no way to guarantee an adult weight for purebreds, too.

There are far too many factors that can affect their growth cycle to know for sure.

However, you can use these techniques to get a good estimate. These methods have been used by breeders and dog owners for decades, so they’re pretty reliable.

No matter what your puppy’s future is looking like, make sure to provide them with the best care possible. A healthy diet, plenty of exercise, and lots of love will ensure that they can reach their full potential.

Also read: Best Dog Food for GoldenDoodles

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