Dog & Cat Age Calculator
Convert your dog or cat's age into human years using modern veterinary guidance — with size adjustment and life stage.
Everyday Uses
Understanding your dog's stage
A 7-year-old Lab isn't "49" — see their real human-equivalent age and what life stage that means.
Vet care timing
Know when your pet crosses into senior territory — the point where twice-yearly checkups start paying off.
Cat age surprises
A 15-year-old cat is roughly a 76-year-old human — helpful context for behavior and care changes.
Kids' questions answered
"How old is Rex in people years?" Finally answer with real veterinary math, not the ×7 myth.
Frequently Asked Questions
Is the "multiply by 7" rule accurate?
No — it is a marketing-era myth. Pets mature far faster than humans early on: a 1-year-old dog or cat is roughly equivalent to a 15-year-old human, and a 2-year-old to about 24. After that, aging slows to roughly 4–7 human years per pet year. The ×7 rule underestimates young pets and can misjudge seniors.
Why does dog size matter?
Larger dogs age faster and live shorter lives — a great mystery of biology, since bigger species usually live longer than smaller ones, yet within dogs the reverse holds. Small breeds often reach 14–16 years while giant breeds average 7–9, so after age two this calculator adds about 4 human years per year for small dogs and up to 7 for giant breeds.
How do cats age compared to dogs?
Cats follow the same fast-start pattern (15 human years for year one, 9 more for year two) and then age at about 4 human years per year — similar to small dogs. Indoor cats commonly reach 15–20 years; a 20-year-old cat is roughly a 96-year-old human.
When is my pet considered a senior?
Vets generally consider cats and small dogs senior around age 10–11, medium dogs around 8–9, and large or giant breeds as early as 6–7. Senior status typically means twice-yearly checkups, bloodwork, joint support, and diet adjustments — catching age-related issues early makes a real difference.