Facts about the animal kingdom

How to Predict a Dog's Size When They Are Mixed Breed

Josie F. Turner
By Josie F. Turner, Journalist specialized in Animal Welfare. April 11, 2024
How to Predict a Dog's Size When They Are Mixed Breed

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If we adopt a purebred dog, one of the benefits in terms of care is knowing how large they are likely to grow. This is an important factor for many of us since we might have space limitations in our home. Larger dogs create larger bills in terms of their upkeep. They are also more prone to various diseases which can increase the likelihood of equally large veterinary bills. This is not to say that smaller dogs will not have their own issues which we need to consider, but knowing the size potential of your dog can be very useful. When our dog is not purebred, knowing when mixed-breed dogs stop growing is much more difficult to determine.

There are many advantages of adopting a mixed-breed dog, so we should not make size the only factor. However, it is an important one in terms of practical care and meeting our responsibilities as dog guardians. This is why AnimalWised finds out how to predict a dog's size when they are mixed breed.

  1. Is it possible to know the size of a mixed-breed dog?
  2. Is it possible to know the genetic ancestry of a mixed breed dog?
  3. Can you predict a puppy's size with their paws?
  4. When do mixed-breed dogs stop growing?

Is it possible to know the size of a mixed-breed dog?

If you adopt an adult dog, you will already know what their maximum size will be. However, it is important to know that different dogs will develop at different rates. Making it more complicated in terms of predicting when a dog will stop growing, larger dogs tend to develop more slowly than smaller dogs. Dogs tend to develop to their full maturity between one and two years. However, some dogs make take as much as three years, especially if they are large.

When we adopt a puppy, there are various barriers in determining their adult size. If we adopted a purebred dog, this will give us some general parameters to help us know what to expect. While there may always be exceptions, specific breeds tend to grow within limits delineated by their breed standard. Especially if we see their parents, we should have a good idea of what to expect in terms of their adult size.

Adopting a mixed-breed dog is different. We can look at the parents of our mixed-breed dog and have an idea of their eventual size. However, the genes which these dogs carry can be dominant or recessive, meaning there may be genes related to size which are not expressed by the parents, but which affect the puppy's development. This is similar to color. Two dogs with golden coats can mate and the mother gives birth to a golden puppy.

This presupposes that we are aware of the parentage of our mixed-breed dog. In rare cases, we might find a puppy which has been abandoned and we have no information about the mother or father dog. However, it is fairly common for a female dog to get pregnant by an unknown male, especially if they are a street dog. In these cases, the size of the male is completely unknown and it can make it very difficult for us to predict the puppy's adult size.

Even if we know the sizes of our mixed-breed puppy's parents, this does not guarantee anything. The genetic information they pass on can be incredibly variable and many surprises may occur. For this reason, it is not always possible to predict the size of a mixed-breed dog. The following ways can help us do our best.

Learn more about canine crosses with our list of top mixed-breed dogs.

Is it possible to know the genetic ancestry of a mixed breed dog?

While we may be more aware of genomic biotesting in humans which can help us determine our family's genetic history. Companies require us to send a DNA sample and the information is analyzed by the company. While not as widely available everywhere, this is a very common test in the United States with a relatively high degree of accuracy.

Since around 2007, this same basic technology has been used in some countries to determine the genetic ancestry of dogs. Although we can observe the influence of some breeds in a mixed-breed dog, simply looking at them will not reveal much. By looking at the genes themselves, we may be able to determine some information which can help us predict their size as an adult.

The purpose of this genetic testing varies according to guardian. Many owners of purebred dogs test them to ensure they are indeed a type of pedigree dog, especially if they want to use them as show dogs or if they are considered breeding them. Owners of mixed-breed dogs may try to determine their genetic history out of pure curiosity, but they may also do so to help predict size.

It is important to note that not all genetic testing for dogs is 100% accurate. They have even been reports of people submitting human DNA and receiving results which claimed they were of a dog[1]. With this in mind, we should be careful about trusting the results.

Can you predict a puppy's size with their paws?

Any prediction is not a guarantee. Using a puppy's paws to predict their adult size is possible, but it is not an exact science and there is some room for error. Still, many have used this technique to give them a better estimation of how they will be when they are older. We can try to predict a puppy's adult size by looking at the size of their paws.

Generally speaking, the larger a puppy's paws, the larger a dog will be when they are adult. This measurement is based on their paw size relative to the rest of their body. For example, a Chihuahua may have larger paws in proportion to their body, but it doesn't mean they will be very big when they mature.

The bone structure of our puppy will also help to guess how large they may be. if they have a more robust frame, it suggests they will grow larger to fill it out. Conversely, a finer bone structure or smaller frame suggests the opposite.

Discover more about what a dog's paws tell us about the animal with our article describe dog paw pads anatomy.

How to Predict a Dog's Size When They Are Mixed Breed - Can you predict a puppy's size with their paws?

When do mixed-breed dogs stop growing?

The extent of the growth process of our mixed-breed dog is linked to the size that our dog should have, but this information can be used as a clue. Depending on the age our pet is when it stops growing, we can predict their adult dimensions with some certainty:

  • Small size: the dog will grow quickly, at 3 months it will have reached half the weight it will have in adulthood and will begin to stop growing at approximately 6 months.
  • Medium size: it will grow actively until it is 7 or 8 months old. However, the height and volume will be established when it turns one year old and this period may be slightly shorter.
  • Large size: the growth process is much slower compared to a small breed, it reaches half its adult weight at approximately 6 months and its growth can last up to two years.

By observing when the growth of our mixed-breed dog stops, we can use it as a guide to predict their adult size. The dog may still be developing after this time and may take longer to reach sexual maturity. However, they should not grow significantly larger after this time, expect in terms of muscle or fat.

While growing too large can be a problem for guardians, it is very important to know that underdevelopment is also troubling. Learn more with our article explaining why a puppy isn't growing anymore.

If you want to read similar articles to How to Predict a Dog's Size When They Are Mixed Breed, we recommend you visit our Facts about the animal kingdom category.


1. Yang, M. (2024). Pet DNA testing company in doghouse after identifying human as canine. Retrieved from: https://www.theguardian.com/lifeandstyle/2024/mar/13/dog-human-dna-test

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How to Predict a Dog's Size When They Are Mixed Breed