Convert your cat’s age into human years with the veterinary standard: 15 for the first year, 9 for the second, 4 for each year after.
How cat years are counted
The old “multiply by seven” rule was borrowed from dogs and was never right for cats. The veterinary convention is front-loaded, because a cat does almost all of its maturing early: the first year is worth about 15 human years, the second adds 9 more, and every year after that adds roughly 4.
Enter your cat’s age and this calculator returns the human equivalent along with the life stage vets use — kitten, young adult, prime, mature, senior or geriatric — which is more useful than the number itself when thinking about diet and check-up frequency.
How to use it
- Enter your cat’s age in years (decimals are fine — use 0.5 for six months).
- Read the human-year equivalent.
- Check the life stage underneath.
The formula
A worked example
The calculator opens with a 4-year-old cat. That is 15 + 9 for the first two years, then 4 × 2 for the next two — 32 human years, a prime adult. A 10-year-old cat works out at 56, and a 16-year-old at 80. Change the age and every figure updates as you type.