How to calculate cat age in human years
The old rule of "multiply by seven" doesn't fit cats. A cat reaches adulthood in its first two years, so the commonly used veterinary approximation is:
- Year 1 equals about 15 human years.
- Year 2 adds about 9, so a 2-year-old cat is roughly 24.
- Every year after that adds about 4 human years.
Example: a 6-year-old cat is 24 + (4 × 4) = 40 in human years. This calculator also scales partial years by month, so a 6-month-old kitten comes out at about 7.5.
Life stages of a cat
Kitten (0-6 months)
Rapid growth, vaccinations, socialization and lots of play.
Junior (7 months-2 years)
Reaching full size and sexual maturity, with high energy and a need for spay or neuter decisions.
Prime (3-6 years)
Peak health. Focus on weight control, dental care and enrichment.
Mature (7-10 years)
Early signs of aging can appear. Annual blood work becomes valuable.
Senior (11-14 years)
Higher risk of kidney disease, arthritis, thyroid and dental problems.
Geriatric (15+ years)
Comfort-focused care, easier access to litter and food, and frequent vet visits.
Frequently asked questions
How long do indoor cats typically live?
Indoor cats commonly live 12 to 18 years, and some reach their early 20s. Outdoor cats face traffic, predators, parasites and injury, so they tend to live fewer years.
Is the 7 cat years to 1 human year rule accurate?
No. Cats mature far faster early on, so the 15 / 9 / 4 method is a better estimate.
When is a cat considered a senior?
From about 11 years old, roughly 60 in human years. Many vets suggest check-ups every six months from then on.
How do I know my rescue cat's age?
A vet can estimate age from teeth, coat, eyes and muscle tone. Enter the estimate here for an approximate result.
Does this calculator store my data?
No. Everything runs locally in your browser and nothing is sent anywhere.
This tool gives general estimates for education only and is not veterinary advice. Talk to your veterinarian about your cat's health.