General · Pets
Dog & cat age calculator.
Convert your dog's or cat's age into human years using the real, veterinary-sourced formula — not the outdated "multiply by 7" myth.
Inputs
Result
Fill the form and press Calculate age.
The real formula, not the "×7" myth
The old "one dog year equals seven human years" rule is a myth — it isn't how aging actually works, and the American Veterinary Medical Association (AVMA) says so directly. Dogs and cats mature very quickly in their first two years and then age more slowly per calendar year after that, so a flat multiplier badly over- or under-states age at both ends of the curve.
The commonly cited AVMA-style formula instead treats the first two years as a steep climb and levels off afterward:
- Year 1 ≈ 15 human years
- Year 2 adds ≈ 9 more (24 total)
- Each year after that adds ≈ 4 human years
Veterinary sources (the AVMA, and AVMA-sourced explainers from the American Kennel Club and PetMD) confirm this same 15 / 24 / +4-per-year shape for both dogs and cats, which is why this calculator uses one formula for both species. For ages under 2, this tool interpolates smoothly along that same curve (for example, a 6-month-old pet is treated as roughly halfway through the first 15-year climb).
Why there's no "size" dropdown
In real life, a dog's size does affect how fast it ages — large and giant breeds tend to age faster in their later years and have shorter lifespans than small breeds. But veterinary sources don't agree on one specific set of size-adjusted numbers (the per-year add-on cited for larger dogs ranges anywhere from 5 to 7+ human years depending on the source), so rather than invent a size multiplier that can't be verified against a single authoritative table, this calculator uses the one well-sourced formula above for every size of dog.
Formula reference
| Pet age | Human years |
|---|---|
| 1 year | 15 |
| 2 years | 24 |
| 5 years | 36 |
| 10 years | 56 |
| 15 years | 76 |
Sources, and when they were checked
The formula above was checked against these sources on 29 September 2026. Veterinary guidance is occasionally revised; if you're reading this long after that date, it's worth a fresh check.
- American Veterinary Medical Association — How to determine your pet's age in human years — source of the "not 7 years per dog year" correction
- American Kennel Club — How to calculate dog years to human years — cites the AVMA 15 / +9 / per-year figures
- PetMD — How old is my cat in human years? — cites AVMA's matching 15 / 24 / +4-per-year figures for cats