Houndyear · Dog age calculator
How old is your dog?
Tell us a little — we'll do the math.
Enter your dog's age and pick a size to see them in human years.
Enter your dog's age and pick a size to see them in human years.
Based on AAHA Canine Life Stage Guidelines and the UC San Diego DNA methylation study. An estimate — not a clinical diagnosis.
Lifespan guides
Browse by breed.
Each guide is built on peer-reviewed veterinary research — VetCompass, Morris Animal Foundation, AAHA — with citations you can verify.
Pitbull
Medium10–14 years
Pit Bulls — the affectionate group of bully breeds including American Pit Bull Terriers, Staffordshire Bull Terriers, and American Staffordshires — typically live 10 to 14 years.
Read about Pitbull →
Yorkie
Small13–16 years
Yorkshire Terriers — affectionately called Yorkies — are among the longest-lived dog breeds, with an average lifespan of 13 to 16 years.
Read about Yorkie →
Shih Tzu
Small10–18 years
Shih Tzus are remarkably long-lived for a flat-faced (brachycephalic) breed.
Read about Shih Tzu →
Pug
Small7–12 years
Pugs live 7 to 12 years on average, with a median lifespan of about 10 years according to a 2025 VetCompass Australia study of 691 Pug deaths.
Read about Pug →
Great Dane
Giant7–10 years
Great Danes — the gentle giants — have one of the shortest lifespans of any dog breed, averaging 7 to 10 years.
Read about Great Dane →
Labrador
Large10–14 years
Labrador Retrievers live 10 to 14 years on average, with a median of 12 years according to a landmark 2018 VetCompass UK study of 33,320 Labradors.
Read about Labrador →
Golden
Large10–12 years
Golden Retrievers live 10 to 12 years on average — a sobering decrease from 16-17 years just a few decades ago.
Read about Golden →
The Science
The old “seven dog years per human year” rule isn't how dogs age.
Dogs mature very fast in their first two years — a one-year-old dog is roughly fifteen in human years, and a two-year-old is around twenty-four. After that, the pace depends almost entirely on body size.
Our calculator combines the AAHA Canine Life Stage Guidelines (2019) with the UC San Diego DNA methylation study (Wang et al., 2020) — the same research framework veterinarians use when discussing aging with pet parents. Small dogs age about 4 human years per dog year after age 2; medium 5; large 6; giant breeds 7.
It's an estimate for everyday use — not a clinical tool. Your vet remains the best source for health-specific guidance.
Reverse calculator
What if you were a dog?
Enter your human age and your favorite breed's size — find out how old you'd be on a dog's timeline.
Try the reverse calculator →
Common questions
The science of dog years.
Quick answers built from the same veterinary research that powers the calculator.
How accurate is the dog age calculator?
It's a science-based estimate, not a medical diagnosis. Our formula combines the AAHA Canine Life Stage Guidelines (2019) with the UC San Diego DNA methylation study (Wang et al., 2020). The result reflects how veterinarians think about canine aging on average — your individual dog may age slightly faster or slower depending on genetics, diet, and health.
Why does size affect my dog’s human age?
Body size is the single strongest predictor of canine lifespan. After age 2, small dogs age roughly 4 human years per dog year, medium dogs 5, large dogs 6, and giant breeds 7. Larger bodies accumulate cellular damage faster and put more strain on organs. A 5-year-old Chihuahua is biologically a young adult; a 5-year-old Great Dane is middle-aged.
Is the old “1 dog year = 7 human years” rule wrong?
Yes, it's a myth. Dogs don't age linearly. They mature very fast in the first two years — a 1-year-old dog is roughly 15 in human years, and a 2-year-old is around 24. After that, aging slows and depends heavily on size. Our calculator reflects the modern veterinary understanding instead of the outdated 7× rule.
At what age is a dog considered a senior?
It depends on size. Toy and small breeds are typically considered senior around age 10. Medium breeds around 8. Large breeds around 7. Giant breeds like Great Danes can be senior by 5 or 6. Senior status is when annual bloodwork and joint screenings become standard.
How can I help my dog live longer?
The single most controllable factor is body weight. The 14-year Purina Lifetime Study found that lean-fed Labradors lived almost 2 years longer than free-fed ones. Beyond weight: daily exercise scaled to your dog's age, dental hygiene, annual vet visits (twice a year past age 8), and breed-appropriate screening for known issues.
Is this medical advice?
No — Houndyear is for educational purposes only. Age estimates are based on averaged research data and don't reflect any individual dog's clinical biological age. Always consult your veterinarian for health decisions.