MicroCalculatorsPet Age Calculator
Convert dog or cat age to approximate human years. Uses species- and size-specific multipliers — not the simple 1:7 rule.
How Dog Years to Human Years Works
Dogs don't age at a constant rate. A dog's first year equals roughly 15 human years because of rapid development to sexual maturity. The second year adds about 9, and each year after adds 4–7 depending on breed size — large and giant breeds age faster than small dogs. A 10-year-old Labrador is approximately 66 in human years; a 10-year-old Chihuahua is closer to 56.
The old "1 dog year = 7 human years" rule is a rough average that loses accuracy at both ends of a dog's life. This calculator uses size-specific curves for a more accurate estimate. For cat age conversion, see our dedicated Cat Age Calculator.
People Also Ask
- How old is my dog in human years?
- Is one dog year really seven human years?
- Do large dogs age faster than small dogs?
Pet Age Calculator — FAQ
- Is the 1 dog year = 7 human years rule accurate?
- No. Dogs mature faster early on. First year ≈ 15 human years; second ≈ 9; then ~4–7 per year depending on size.
- Do indoor cats live longer than outdoor cats?
- Generally yes. Indoor cats avoid many hazards and often live into their teens or twenties.
- How can I tell if my pet is a senior?
- Dogs: ~7+ years for large breeds, ~10+ for small. Cats: ~11+ years. Watch for changes in activity and appetite.
Want to learn more?
Read our full guide: Pet Age in Human Years — why "multiply by 7" is wrong, accurate charts for dogs and cats, and how size affects aging.
Last updated: February 2026