How to Know How Big a Dog Will Be

Reviewed and approved by the biologist Georgelin Espinoza Medina

Written by Alba Muñiz

Last update: 04 June, 2023

The million-dollar question when deciding to adopt a puppy may be what size a dog will be when it grows up. As puppies, all canines are adorable and manipulable, but some will grow into real giants. So, before you give in to the urge to rush a dog into your home, get to know how big a dog will be, and avoid future complications.

Factors to take into account when raising big dogs

If the puppy grows to an unsuspected size, you must ensure you have enough space in your house so that both humans and the animals living there can be comfortable.

Also, keep in mind that in many indispensable issues for their welfare, you’ll have to invest more money, such as:

• Accessories
• Extra food
• Veterinary expenses
• Transportation (especially if you don’t have your own vehicle)

With these caveats in mind, here are some facts to find out how big a dog will be when it grows up.

How can I find out how big a dog will be when it grows up?

If it’s a purebred animal, or you know its parents, then you can get an approximate idea of the weight and height that your puppy will reach in adulthood. For example:

• The females will probably be similar to their mother in these aspects and the males to their father.
• If there are significant size differences between the parents, your dog will most likely be intermediate in size.
• Find out the average weight and height of your dog’s breed at different stages of growth and compare the data with the records you keep on your puppy.

If there are differences, then your dog will most likely be a little smaller or larger than usual for the breed to which it belongs. If the animal is a mixed breed, try averaging the standard sizes of each.

Ways to calculate the adult size of a mixed breed puppy

It gets a little complicated when you have a beautiful puppy with no lineage in sight and you have no idea who its parents are. However, there are always clues to find out these questions.

For example: if the puppies have very long legs and ears compared to their bodies, they’ll almost certainly be quite big when they’re adults.

You can also make a rough estimate of how much your puppy will weigh by the time it reaches one year of age. Follow the steps below:

• Find out the puppy’s weight
• Divide that figure by the puppy’s age in weeks
• Multiply that result by 52, which is the number of weeks in a year

In any case, remember that small dogs grow much faster, so they may be completing their growth before 12 months and that very large animals may continue to grow until they are two years old.

Tracking a puppy’s weight and height

In addition, you can evaluate your puppy’s growth over the months to get a more accurate idea of the size they’ll reach as an adult. Like all animals, dogs have growth curves that help us get an idea of how much they’ll grow.

There are specific formulas to make this calculation, or you can consult standard growth curves and compare them with the weight of your dog according to how old they are.

Also keep in mind that:

• Most dogs reach 75% of their final height at 6 months
• Nutrition, health, and other factors can affect an animal’s growth

Size is the least of it

If you love animals, surely the height, weight, and breed of your pet will be a minor factor for you. You’ll love your dog and they’ll love you. And you’ll surely take responsibility for your four-legged friend regardless of its size. But it never hurts to consider some factors in order to take the best possible care of them throughout their life.