How Long Do Dogs Live? Lifespan by Size Category

Last updated April 20, 2026 · 7 min read

The biggest predictor of how long a dog will live is body size. A small breed averages 14–17 years. A giant breed averages 7–10. That gap of nearly a decade is bigger than any other factor in canine longevity, including breed, diet, or lifestyle. Here’s the data on why; and how to maximize the years you have.

Average lifespan by size category

Small breeds (under 20 lbs)

Average lifespan: 13–17 years

Chihuahua, Yorkshire Terrier, Pomeranian, Toy Poodle, Maltese, Shih Tzu, Miniature Schnauzer, Cavalier King Charles Spaniel, Boston Terrier. Many small dogs live well past 15, and some reach 18 or 19. Dental disease and tracheal collapse are the most common breed-related conditions; congenital heart conditions like patent ductus arteriosus and mitral valve disease are also frequent. Cavaliers as a breed have a shorter average due to a high rate of mitral valve disease.

Medium breeds (20–50 lbs)

Average lifespan: 10–14 years

Beagle, Cocker Spaniel, Border Collie, Australian Shepherd, English Springer Spaniel, Standard Schnauzer, Bulldog, French Bulldog. The crossover zone where size starts to noticeably affect longevity. Working-line medium dogs (Border Collies, Aussies) tend to live longer than show-line or brachycephalic medium dogs (Bulldogs).

Large breeds (50–90 lbs)

Average lifespan: 8–12 years

Labrador Retriever, Golden Retriever, German Shepherd, Boxer, Rottweiler. Average drops by 2–3 years compared to medium. Hip and elbow dysplasia, cancer (especially in Golden Retrievers, where lifetime cancer risk approaches 60%), and bloat (gastric dilatation-volvulus) become more common.

Giant breeds (over 90 lbs)

Average lifespan: 7–10 years

Great Dane, Saint Bernard, Newfoundland, Irish Wolfhound, Mastiff. Notably short. Irish Wolfhounds average around 7 years; Great Danes around 8. Cardiac issues (dilated cardiomyopathy), bone cancer (osteosarcoma), and bloat are the leading causes of premature death.

Why bigger dogs live shorter lives

This is one of the most counterintuitive findings in mammalian biology. Across most species, larger animals live longer. Elephants outlive mice by decades. Within domestic dogs, the pattern flips: bigger means shorter. The current best understanding combines several mechanisms:

• Faster cellular aging. Large dogs grow faster as puppies, and the same growth factors (IGF-1 in particular) that drive size also drive accelerated cellular wear. Studies have shown that lifespan correlates with IGF-1 levels across breeds.
• Higher cancer rates. Larger dogs have more cell divisions over a lifetime and proportionally higher cancer risk. Osteosarcoma in particular is far more common in big dogs.
• Cardiac load. Larger hearts move more blood; dilated cardiomyopathy and other cardiac conditions appear earlier and more frequently in big dogs.
• Orthopedic burden. More mass on the same skeletal structure leads to earlier joint wear.

What adds years (the evidence-supported list)

• Lean body weight. The strongest lever you control. About 2 extra years on average from preventing chronic overweight.
• Spay or neuter at appropriate timing for the breed. Removes reproductive cancer risk and reduces certain behavioral risks; specific timing benefits depend on breed and size.
• Regular dental care. Reduces systemic inflammation; dental disease is associated with kidney and cardiac issues.
• Annual vet visits through middle age, twice-yearly with bloodwork starting in the mature stage.
• Heartworm and parasite prevention year-round.
• Mental enrichment. Dogs with regular cognitive stimulation show less cognitive dysfunction in old age.

What doesn’t affect lifespan as much as people think

• Mixed vs purebred. The difference exists but is smaller than the effect of size. A 70-pound mutt and a 70-pound purebred have more similar lifespans than a 70-pound mutt and a 10-pound mutt.
• Premium kibble vs mid-tier kibble. Provided both are AAFCO-complete and the dog is at a healthy weight, the brand effect on lifespan is small.
• Grain-free diets. No lifespan benefit shown. Some grain-free diets have been linked to dilated cardiomyopathy in dogs. The FDA continues to investigate.
• Specific supplements beyond joint support and omega-3 don’t have strong evidence for lifespan extension.

Breed-specific outliers

Within size categories, breed makes a real difference:

• Golden Retrievers (large breed) have a notably shorter average lifespan (~10 years) due to high hereditary cancer rates.
• Labrador Retrievers (large breed) often reach 12–13 years, longer than the size category average.
• Cavalier King Charles Spaniels (small breed) average shorter (~10 years) due to mitral valve disease.
• Border Collies (medium-large) often reach 14–15 years with proper care. Longer than most working-size dogs.
• Rottweilers (large to giant) typically live 8–10 years with osteosarcoma as a common cause of premature death.

How size shapes the math

Size is the headline predictor: small dogs commonly reach 15+, while giants rarely make it to 10. Within any size category, weight management, dental care, and regular vet contact account for most of the within-size variation. If you have a large or giant breed, the lifespan is shorter, but the levers you control still matter and still add real years.

Use our dog age calculator to see your dog’s age in human years using the size-adjusted formula; the result is dramatically different for a Yorkie vs a Great Dane at the same calendar age.

Written by the Dogs Age Calculator editorial team · How we research & fact-check