The quick chart
- 1 dog year = about 15 human years (all sizes)
- 2 dog years = about 24 human years (all sizes)
- After that, each year adds about: 4 human years (small dogs), 5 (medium), 6 (large) or 7 (giant)
So a 7-year-old small dog is about 44 in human years, while a 7-year-old giant breed is about 59. Try any age in our dog age calculator.
Life stages and what they mean
- Puppy: vaccines, training, socializing and lots of food for growth
- Young adult and adult: yearly checkups, dental care, a healthy weight and plenty of exercise
- Senior: more frequent vet visits, joint support and diet changes, depending on your vet's advice
Why big dogs age faster
Scientists are still studying why, but larger breeds tend to have shorter lifespans and reach their senior years sooner. That's why the chart adds more human years per dog year for bigger dogs.
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Questions people ask
How old is a 5-year-old dog in human years?
About 36 for a small dog, 39 for a medium dog, 42 for a large dog and 45 for a giant breed, using the common size-based chart.
Why is the dog years times 7 rule wrong?
Dogs mature very quickly in their first two years and then age more slowly, and the pace depends on size. A flat 7-to-1 ratio ignores both.
At what age is a dog a senior?
Giant breeds can be seniors by 5 or 6, large dogs around 7 or 8, and small dogs often around 10 or later.
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The Paw Plan shares general information, not veterinary advice. Every pet is different, so check with your vet about your pet's health, diet and care.