A dog’s life expectancy is affected by a number of factors, including size, breed, gender, and whether or not the dog has been spayed or neutered.

A study of more than 3,000 dogs in the UK found that the average canine lifespan is 11 years, 1 month and that only 8% of all dogs live beyond the age of 15 (Michell, 1999). However, certain breeds have longer or shorter life expectancies than this average, and spay-neuter surgery also has an impact on longevity.

How Old Is My Dog In Human Years?

Small dogs live longer than large dogs on average because of most large breeds age more rapidly. According to WebMD (20 March 2010), during the first year of life, dogs of various sizes age the equivalent of approximately 15 years. By age 2, dogs are around 24 years of age. Age 3 equates to 28 years, age 4 to 32, and age 5 to 36. However, after age 5:

  • A small dog (less than 21 pounds) continues to age approximately 4 years for every human year.
  • A medium-sized dog (21-50 pounds) ages around 4.5 years for each human year.
  • A large dog (51 pounds and up) ages between 5 and 9 years for each human year.

This difference in aging is most pronounced among some of the largest and smallest breeds. For example, a Great Dane lives 7-10 years on average, whereas a Chihuahua may live 18 years.

How Old Is My Dog In Human Years?

How Old Is My Dog In Human Years?

Which Dog Breeds Live the Longest?

Overall, purebreds tend not to live as long as mixed breeds, though there are exceptions to this rule, including the Jack Russell Terrier, the Whippet, and the Miniature Poodle (Michell, 1999). The longest-lived dog breeds, which (barring accident or other unforeseen misfortune) typically enjoy 15-18 years of life, include:

  • Chihuahua
  • Dachshund
  • Miniature/Toy Poodle

Dog breeds that can live for 14-16 years include:

  • Boston Terrier
  • Cairn Terrier
  • Cocker Spaniel
  • Irish Setter
  • Maltese Terrier
  • Parson Russell Terrier
  • Schnauzer
  • Shih Tzu
  • Standard Poodle
  • Welsh Corgi
  • West Highland White Terrier
  • Yorkshire Terrier

Breeds that may enjoy 12-15 years of life include:

  • Beagle
  • Bichon Frise
  • Collie
  • Papillon
  • Pomeranian
  • Pug
  • Shetland sheepdog

Do Spayed or Neutered Dogs Live Longer Than Unfixed Pets?

Spay-neuter surgeries add 1 to 3 additional years of life on average, according to the North Shore Animal League (n.d.). This advantage is particularly strong for females – spayed females live longer than unspayed females and both neutered and unfixed males (Michell, 1999)

Veterinarian Margaret Kustritz (cited in Keith, 8 January 2008) notes that although spayed and neutered pets do live longer on average, this is more likely attributable to behavior changes after the surgery than health-protective effects. Spay-neuter surgeries reduce the risk of mammary cancer and eliminate the risk of testicular, uterine, and ovarian cancers, but they increase the risk of prostate, bladder, and bone cancers, so there are health benefits and risks for both fixed and unfixed animals. However, neutered and spayed dogs are less likely to roam and get hit by cars, to be injured in fights, or to be euthanized due to intractable aggression and other behavioral problems. Kustritz notes that the greater longevity among fixed pets may also be attributable to the fact that owners who have their pets spayed or neutered are typically committed to taking good care of them.

Do Spayed or Neutered Dogs Live Longer Than Unfixed Pets?

Do Spayed or Neutered Dogs Live Longer Than Unfixed Pets?

How Can I Help My Dog Live Longer?

In addition to spaying or neutering, there are plenty of common-sense things you can do to help your dog live longer, including providing plenty of opportunities for exercise, regular tooth cleaning (be sure to use products specifically formulated for dogs – human toothpaste can make dogs ill), and regular veterinary check-ups.

While there are no large-scale studies supporting any specific food for canine longevity, dogs fed appropriate, nutritionally complete foods will have a better chance at a long life than those regularly consuming the canine equivalent of junk food. Lippert and Sapy’s (2003) study of 522 dogs in Belgium found that dogs fed a species-appropriate homemade diet lived nearly 3 years longer on average than dogs fed commercially available dog foods. This result likely reflects the poor quality of so many dog foods on the market, many of which are loaded with artificial and filler ingredients.

To choose a good dog food, check the ingredients list – if meat, poultry, fish, or eggs is the first ingredient listed, the food is more likely to be high quality. Grain sources should be whole (i.e., brown rice, barley, etc.) rather than refined, and the food should be free of artificial ingredients.

This article is provided for informational purposes only and is not intended as a substitute for veterinary consultation. Canine health concerns should be referred to a qualified veterinarian.

How Long Do DOGS Live? Explained


  • Drs. Foster & Smith, Educational Staff, “Dog Food, How to Choose,” DrsFoster&Smith.com, 2012.
  • Eckstein, S., Reviewed by Elizabeth A. Martinez, DVM, “Dogs and Life Span: Which Breeds Live Longest?” Pets.WebMD.com, 2009.
  • Keith, C., “Spay/Neuter: What Does the Science Say?” PetConnection.com, 8 January 2008.
  • Lippert, G., & Sapy, B., Relations Between the Domestic Dogs’ Well-Being and Life Expectancy, Essay for the Prince Laurent Foundation Price, 2003.
  • Michell, A.R., “Longevity of British Breeds of Dog and Its Relationships with Sex, Size, Cardiovascular Variables, and Disease,” Veterinary Record, 145(22), pp. 625-629, 1999.
  • North Shore Animal League, “Benefits of Spay/Neuter Surgery for Cats and Dogs,” SpayUSA.org, n.d.
  • Paylo, J., “How Long Will My Dog Live?” PetPlace.com, 2012.
  • WebMD, “How to Calculate Your Dog’s Age,” Pets.WebMD.com, Reviewed by Audrey Cook, BVM&S on March 17, 2010.