What Is the Difference between Medium and Large Breed Dogs?

Dogs come in a range of sizes usually classified in one of four ways: small, medium, large and giant. While the size difference between a small breed such as a Yorkshire terrier and a giant breed like the Great Dane is clear, the distinctions between medium and large breeds are not always so apparent. Although the main difference between medium and large breed dogs is their size, the differences also affect life expectancy.

Defining Medium Breeds

Typically, the broad category of medium size breeds includes dogs that range from around 25 to 55 pounds at maturity. Others expand the range to between 20 and 60 pounds. The category includes diverse types of dogs, including:

  • American Staffordshire terrier
  • Australian shepherd
  • Basenji
  • Basset hounds
  • Beagle
  • Border collie
  • Boxer
  • Bulldog
  • Dalmatian
  • Pembroke Welsh corgi
  • Portuguese water dog
  • Siberian husky
  • Whippet

Medium size dogs such as those listed above can live, on average, between 10 and 12 years. In 2014, Banfield Pet Hospital released a report that included the top medical problems that needed to be treated in medium size dogs by the hospital's staff. The most common problems were eye infections and bladder inflammations.

Defining Large Breeds

The large breed category includes dog breeds that weigh more than 50 to 60 pounds but less than 90 pounds at full size. Dogs weighing more than 90 pounds are considered giant breed dogs. This category of dog breeds would include:

  • Akita
  • Alaskan malamute
  • Bernese mountain dog
  • Bloodhound
  • Doberman pinscher
  • German shepherd
  • English setter
  • Old English sheepdog
  • Golden retriever
  • Labrador retriever
  • Greyhound
  • Rottweiler
  • Weimaraner

These types of large breed dogs typically live 9 to 12 years so their life expectancy is not much different than that of medium breeds. However, the Banfield report indicated that large breed dogs were at much greater risk of being overweight, especially as they aged, than other size categories. The report also showed that large breed dogs were more likely to be treated for gastrointenstinal problems and ear infections.

Another difference between medium and large breed dogs is that the latter mature slower. Large breed dogs do not reach maturity until around 15 months of age compared to 12 months or less for medium breeds.

Other Lifestyle-Related Differences

Besides size and life expectancy, other differences between medium and large dogs are more breed specific. Exercise requirements, for example, vary more by breed than by size. For example, dobermans have very high energy levels and are classified as large dogs but so do the medium-size border collies. Similarly, Siberian huskies and Alaskan malamutes have high and medium energy levels, respectively. Likewise, large greyhounds and medium basset hounds are both considered low energy dogs. However, if you do have a larger breed you need to be careful exercising them until they are mature because their skeleton may not have developed enough to support their body's weight and because those developing joints can be easily injured.

The ideal living environment for different dogs can vary by size. As with energy levels, some medium size dogs do well in apartments just as some large breed dogs do. Greyhounds, for instance, are considered ideal for apartments as are some giant breeds such as the Great Dane. If you choose a high energy dog, regardless of size, you need plenty of living space and room for exercise, such as a fenced yard or nearby dog park. Even though some larger breeds make the best apartment dwellers, many apartments and landlords place size restrictions on pets. Dogs weighing more than 75 pounds are often not allowed in rental properties, which rules out many large breeds. Other apartments use breed restrictions with a mix of medium and large breeds, such as pit bulls, Rottweilers, German shepherds, doberman pinschers, Siberian huskies and bulldogs, being the most commonly refused.