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Dog & Cat Age Calculator
If your dog or cat were a person, how old would they be right now?
Why "one year equals seven human years" is wrong
Simply multiplying a pet's age by seven is a common myth that doesn't reflect how dogs and cats actually age — the first year of a dog or cat's life is equivalent to about 15 years of human growth and maturity, not seven. This tool uses a more realistic formula that accounts for the faster aging in early life and, for dogs, breed size.
Why does dog breed size matter?
Unlike cats, which age at a fairly similar rate across breeds, large and giant dog breeds typically age faster than small breeds and have shorter lifespans — which is why this tool asks dogs for their breed size.
Frequently asked questions
How accurate is this formula?
This is a general, fun estimate based on common growth and aging patterns, not an exact medical formula for any specific animal — health, genetics and lifestyle can all change the real result.
Why is a dog or cat's first year of life equal to about 15 human years?
Because dogs and cats reach physical and sexual maturity very quickly in their first year of life — growth that takes a human about 15 years.
How do I know my dog's breed size?
Go by your dog's approximate adult weight: up to 22 lb (10 kg) is small, 22–55 lb (10–25 kg) is medium, 55–88 lb (25–40 kg) is large, and over 88 lb (40 kg) is giant.
Does this work for mixed breeds too?
Yes — just use your dog's approximate adult weight to pick the closest size category, regardless of exact breed.