Estimate your dog's age in human years and life stage. Large dogs often age faster, so size matters.
Estimated human age
29
human years
Life stage
Adult
This is an educational estimate. Breed, body condition, medical history, and activity level can change aging patterns.
How accurate is this dog age calculator?
The estimate is a guideline grounded in widely-cited canine life-stage models from the American Animal Hospital Association (AAHA) and University of California, Davis School of Veterinary Medicine, which discard the old "one dog year = seven human years" formula. Real biological age depends on breed, body size, neutering status, weight, and individual genetics. Treat the result as a planning tool — use it to time wellness checks, dietary changes, and behavior monitoring, not as a substitute for a veterinarian's exam.
Why does size change the dog years calculation?
Small dogs (under 10 kg / 22 lb) often live 13-16 years, while giant breeds (over 40 kg / 88 lb) average 7-10 years. Larger dogs reach senior status faster — a 7-year-old Great Dane is biologically closer to a 65-year-old human, while a 7-year-old Chihuahua is closer to 44. The calculator weights size because cellular aging, joint wear, and disease prevalence all scale with body mass in dogs.
What senior dog signs should I watch for?
Senior dogs commonly show subtle posture and behavior changes before medical issues become urgent. Watch for stiffness when standing up, panting at rest, hiding, reluctance to climb stairs, sleep changes, appetite shifts, and increased irritability around handling. Many of these overlap with stress signals — see our checker for visible cues and our guide on when to escalate to a veterinarian.
How does dog aging compare to cat aging?
Cats age more uniformly than dogs because feline body sizes vary less. A 7-year-old cat is roughly 44 in human years regardless of breed, while a 7-year-old dog can be anywhere from 44 to 65 human years depending on size. Cats also typically live longer than large dogs (14-18 years vs 7-10), so a separate cat age calculator gives a more accurate cross-species comparison.
When should I take my senior dog to the vet?
AAHA recommends twice-yearly wellness visits once a dog enters senior life stage — that's around age 7 for large breeds and age 10 for small breeds. Sooner if you see sudden behavior change, weight loss, new lumps, persistent coughing, pain signs, or any combination of warning signs at the same time. The calculator's life-stage label is a useful prompt for booking the next check-up.