Pet Age Calculator
Convert your dog or cat's age to the human equivalent using breed-size adjusted formulas.
Results
What is it?
The Pet Age Calculator converts your pet's actual age into an approximate human-equivalent age. The classic 'multiply by 7' rule is inaccurate — pets age very rapidly in their first two years and then slow down. This calculator uses a more realistic model: the first year equals approximately 15 human years, year two adds about 9 more, and subsequent years add 4–6 per year depending on dog size (larger breeds age faster).
How to use
Enter your pet's age in years (decimals supported, e.g., 1.5 for 18 months). Select the pet type and size category. The result shows the approximate human-equivalent age.
Example scenario
A 3-year-old medium-sized dog (25 lb Golden mix): 24 + 3 × 5 = 39 human years — in their prime, equivalent to a late-30s adult. A 10-year-old large dog: 24 + 10 × 6 = 84 human years — a senior citizen who needs more frequent vet check-ups.
Pro tip
Large and giant breeds (Great Danes, St. Bernards) have shorter lifespans than small breeds — a 7-year-old Great Dane is already elderly. Annual vet visits are recommended for adult pets; twice-yearly for seniors (dogs 7+, cats 10+). A 2019 UC San Diego study suggests using the formula: human age = 16 × ln(dog age) + 31, which aligns even better with biological aging markers.