Dogs are known for being loyal, dependable, and a vital part of the lives of many people. They also famously come in a variety of sizes, ranging from the kind you can carry around in a handbag to the kind that is big enough to kick you out of bed.

Factors to Consider

There is truly no way to tell how big a dog is going to be, outside of providing an estimate based on the breed. However, certain factors help to determine how big your dog will be--including environment, lifestyle, nutrition and genetics.

Purebred Versus Mixed Breed

By going with a purebred dog, you get a more accurate idea of the eventual size, as opposed to a mixed breed. For example, a Yorkie-dachshund mix might turn out to be two pounds as an adult--or 12 pounds. According to veterinarian Debbye Turner, you can estimate size with better accuracy with a purebred than with a mixed breed, since you might not be able to tell what bloodlines are in your mixed breed dog.

Lifestyle and Nutrition

By providing a quality dog food and giving your dog a healthy lifestyle, you are helping him to achieve a size that is ideal for him. Cheaper dog foods and sedentary lifestyles might result in overweight but underdeveloped dogs.

Genetics

Obviously, the size of a dog's parents affects her size in most cases. To get an idea of the size of your dog, look at her parents, if possible.

Breed

The best way to determine how big your dog might become is to take a look at the breed standard. For the most part, if your dog comes from a large breed, the odds are great that you'll wind up with a large dog.

Source:

"The Six Essential Factors in Choosing a Dog"

"How to Pick a Puppy"

"Puppy Weight Estimates"

More Information:

"How Big Will My Puppy Get?"