About Dog & Cat Age

Dog & Cat Age turns a pet’s age into a human-age estimate and a life stage, and shows exactly where each number comes from. “Multiply by seven” is a myth: dogs and cats age fastest in their first two years and more slowly after that.

Where the numbers come from

• Dogs: the American Veterinary Medical Association’s “Pets age faster than people” chart, which is for a medium-size dog of 21 to 50 lb, side by side with the DNA-methylation formula from Wang et al., Cell Systems, 2020.
• Dog size and life stage: AVMA’s senior ages for small, medium, large and giant dogs, and the 2019 AAHA Canine Life Stage Guidelines.
• Cats: International Cat Care’s cat age chart and life stages, plus the 2021 AAHA/AAFP Feline Life Stage Guidelines.

AVMA does not publish a year-by-year human age for small, large or giant dogs, and the size charts on many pet sites don’t name a veterinary source. So this site doesn’t invent per-size numbers: dog size changes the life stage, not the human-age figure.

How we keep it accurate

Every number links to its original source, and the math is shown next to each result so you can check it. Where a published chart lists whole years only, months are filled in on a straight line, and the page says so. We fix errors as soon as we find them.

Human-age equivalents are estimates, not veterinary advice. Your vet is the best judge of how your own pet is aging.

Free to use

The tools are free and need no sign-up. Ads from Google AdSense pay for keeping the site online. See the privacy policy for what that means.