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How old is your dog in human years?

Enter your dog's age and size, and see their real age in human years. The "multiply by 7" rule you grew up with is wrong, sometimes by a decade or more. Dogs age fast in their first two years, then slow down, and giant breeds age dramatically faster than small ones late in life.

Your dog's age:

Your dog's size:

🐶 Your dog is:

years old in human years.

The old "multiply by 7" rule would say 35. It's off by 4 years.

Aging math based on the American Veterinary Medical Association's general guidance and the size-adjusted formulas from veterinary research.

Why does dog size matter?

Smaller dogs live longer. A Chihuahua often makes it to 16 or 17 years, while a Great Dane is considered elderly at 7. The reason isn't fully understood, but researchers think it comes down to how fast large breeds grow during puppyhood. Their bodies are pushed harder to reach adult size, and that early acceleration appears to shorten their later years.

The classic "multiply by 7" shortcut ignores all of this. It treats a 10-year-old Yorkie and a 10-year-old Saint Bernard as the same human age, when in reality the Yorkie might be 56 in human years and the Saint Bernard closer to 80.

FAQ:

How accurate is this calculator?

Very accurate for adult dogs. The formula uses size-adjusted aging rates that match real veterinary research much better than the "multiply by 7" rule, which is wrong by 5-15 years for most dogs.

Why does my puppy show such a high human age?

Puppies age incredibly fast in their first two years. By age 2, a dog is roughly equivalent to a 24-year-old human regardless of size. That early phase is why the "multiply by 7" rule underestimates young dogs so badly.

Do mixed-breed dogs follow the same aging curve?

Mostly, yes. The biggest factor is adult weight, not breed purity. A 60-pound mutt ages similarly to a 60-pound purebred. Pick the size category that matches your dog's adult weight.

What about giant breeds like Mastiffs and Great Danes?

Giant breeds age the fastest of all. A 7-year-old Great Dane is roughly equivalent to a 62-year-old human, while a 7-year-old Chihuahua is closer to 44. Many giant breeds are considered seniors by age 5 or 6.

Why isn't this calculator just one formula?

Because dogs don't age linearly. The first two years are dramatic, then the curve flattens but the slope depends on size. A single formula would have to be wrong somewhere to be right elsewhere.

Want to go deeper?

If your dog's real human age surprised you, the rest of the picture is just as interesting. Each of these articles pairs naturally with what you just calculated.