Dog & Cat Age Calculator
How old is my pet
in human years?
Enter your dog or cat's age (and size, for dogs) to convert it into human years.
🔒 Your inputs never leave your browser — nothing is sent to a server
Pet Age Ledger
Results update instantly as you type
In Human Years
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Life Stage
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Why not just multiply by 7?
The old "multiply by 7" rule is a myth. Dogs and cats mature rapidly in their first two years, reaching adolescence, then age more slowly afterward. This calculator uses the veterinary-standard formula: 15 years for the first year, +9 for the second, then a steady rate per year after that.
Why does size matter for dogs?
Larger dog breeds tend to age faster in their later years than smaller breeds, so this calculator adds more "human years" per year for bigger dogs after age 2.
Frequently Asked Questions
How accurate is this result?
This is a reference estimate based on commonly cited veterinary formulas. Individual health and breed can affect actual aging.
Is my data stored or sent anywhere?
No. All calculations happen entirely in your browser.
Does this work on mobile?
Yes, the layout automatically adapts to your screen size.