Dog Age Calculator

No — that's a myth. Dogs age rapidly early and slow down later, and size matters a lot. A dog is roughly 15 human years old at one, and about 24 at two, then adds fewer human years per year, more for larger breeds. The flat times-7 rule badly overstates a young dog's maturity.

Larger dogs age faster in their later years and have shorter lifespans, while small dogs live longer and age more slowly. So after age two, a small dog adds about 4 human years annually and a giant breed closer to 7. This calculator adjusts by the size you choose.

It's a well-accepted approximation for perspective, not a precise or medical figure. Real aging varies by breed, genetics, and health. Use it for fun and a rough sense of your pet's life stage, and rely on your veterinarian for actual health guidance.

Cats follow a single size-independent curve since breeds vary far less in weight: roughly 15 human years at age one, 24 at two, then about +4 per year — so a 3-year-old cat is around 28 and a 15-year-old about 76. Dogs use a size-adjusted rate instead (4 to 7 human years per year after age two), which is why the dog mode asks for weight and the cat mode doesn't.