How is this calculated?
For dogs, this calculator uses the formula "human age = 16 Γ ln(dog's age) + 31." This formula was proposed in 2020 by researchers at the University of California, San Diego (UCSD), based on comparing the rate of DNA methylation changes between dogs and humans. It's considered more precise than the old rule of thumb of "one dog year equals seven human years."
For cats, this calculator follows the common veterinary reference table: the first year of a cat's life counts as 15 human years, the second year adds 9 more (for a total of 24), and each year after that adds 4 more human years.
These formulas are estimates based on general averages β actual aging rates can vary by breed, size, and health condition.
Frequently Asked Questions
Why is the calculation different for dogs and cats?
Dog breeds vary enormously in size and lifespan, so a logarithmic formula is considered more accurate. Cats vary less in size between breeds, so the traditional step-based conversion table is still widely used.
Can I calculate the age of a pet under 1 year old?
Yes, you can enter a decimal age. However, for very young pets just a few months old, growth happens so quickly that the result may not perfectly match their actual developmental stage.