Cat Age Calculator
Convert your cat's age to human years using the AAHA/AAFP Feline Life Stage Guidelines. Find out what life stage your cat is in and get age-appropriate health recommendations.
Your Cat
Health Tip: Annual wellness exams are recommended. This is the stage for spay/neuter if not already done.
Lifestyle Note: Indoor cats typically live 12-18 years. Keeping your cat indoors significantly reduces risks from traffic, predators, and infectious diseases.
Cat years to human years chart
| Cat Age | Human Equivalent | Life Stage |
|---|---|---|
| 3 months | ~4 years | Kitten |
| 6 months | ~8 years | Kitten |
| 1 year | ~15 years | Young Adult |
| 2 years | ~24 years | Young Adult |
| 3 years | ~28 years | Young Adult |
| 4 years | ~32 years | Young Adult |
| 5 years | ~36 years | Young Adult |
| 6 years | ~40 years | Young Adult |
| 7 years | ~44 years | Mature Adult |
| 8 years | ~48 years | Mature Adult |
| 9 years | ~52 years | Mature Adult |
| 10 years | ~56 years | Mature Adult |
| 11 years | ~60 years | Senior |
| 12 years | ~64 years | Senior |
| 13 years | ~68 years | Senior |
| 14 years | ~72 years | Senior |
| 15 years | ~76 years | Geriatric |
| 16 years | ~80 years | Geriatric |
| 17 years | ~84 years | Geriatric |
| 18 years | ~88 years | Geriatric |
| 19 years | ~92 years | Geriatric |
| 20 years | ~96 years | Geriatric |
How We Calculate Your Cat's Age in Human Years
The old "multiply by 7" rule doesn't work for cats any more than it does for dogs. Cats mature very quickly in their first two years — a 1-year-old cat has already reached the developmental equivalent of a 15-year-old human. Our calculator uses the AAHA/AAFP Feline Life Stage Guidelines (2021), which divide a cat's life into a piecewise formula reflecting real biological development.
The AAHA/AAFP Formula
The first year of a cat's life equals roughly 15 human years. The second year adds about 9 more, bringing a 2-year-old cat to 24 human years. After age 2, each additional cat year equals approximately 4 human years. This formula captures the rapid kitten-to-adult maturation followed by steadier aging.
Feline Life Stages
The AAHA/AAFP guidelines define five feline life stages: Kitten (0–1 year), Young Adult (1–6 years), Mature Adult (7–10 years), Senior (11–14 years), and Geriatric (15+ years). Each stage carries different health priorities — from vaccination schedules for kittens to kidney and thyroid monitoring for geriatric cats.
Indoor vs. Outdoor Lifespan
One of the biggest factors in a cat's lifespan is whether it lives indoors or outdoors. Indoor cats typically live 12–18 years, with many reaching their early 20s. Outdoor cats average only 5–10 years due to traffic, predators, infectious diseases, and parasites. While the human-years conversion formula doesn't change based on lifestyle, understanding these risks is essential for cat owners making care decisions.
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Sources & Methodology
- Quimby, J. et al. (2021). "2021 AAHA/AAFP Feline Life Stage Guidelines." Journal of the American Animal Hospital Association, 57(2), 51-72
- International Cat Care — Feline Life Stage Guidelines (icatcare.org)
- AVMA Cat Age Conversion Chart (avma.org)
Cat age conversion is based on the 2021 AAHA/AAFP Feline Life Stage Guidelines. Age groupings are approximate — individual cats may age differently based on breed, genetics, diet, and lifestyle. Indoor cats generally live longer than outdoor cats. Consult your veterinarian for personalized health recommendations.
Cat Age Calculator FAQ
How do you calculate a cat's age in human years?
According to the 2021 AAHA/AAFP Feline Life Stage Guidelines, a cat's first year equals about 15 human years, the second year adds 9 more (totaling 24 human years at age 2), and each year after that adds approximately 4 human years. This piecewise formula accounts for the rapid maturation cats experience in their first two years of life.
How long do cats live?
The average lifespan of a cat depends heavily on whether they live indoors or outdoors. Indoor cats typically live 12-18 years, with many reaching their early 20s. Outdoor cats have a significantly shorter average lifespan of 5-10 years due to increased risks from traffic, predators, parasites, and infectious diseases. Factors like breed, genetics, diet, and veterinary care also play important roles.
When is a cat considered a senior?
According to the AAHA/AAFP Feline Life Stage Guidelines, cats enter the “Mature Adult” stage at 7-10 years, the “Senior” stage at 11-14 years, and the “Geriatric” stage at 15 years and older. Most veterinarians recommend beginning senior wellness screenings around age 7-10, when cats are roughly equivalent to a human in their mid-40s to late 50s.
Do indoor cats live longer than outdoor cats?
Yes, significantly. Indoor cats live an average of 12-18 years, while outdoor cats average only 5-10 years. Indoor cats are protected from traffic accidents, predator attacks, infectious diseases (like FIV and FeLV), parasites, and exposure to toxins. Providing enrichment, vertical spaces, and interactive play can help indoor cats stay physically and mentally healthy.
Is the "multiply by 7" rule accurate for cats?
No, the “multiply by 7” rule is a myth for both cats and dogs. Cats mature much faster in their first two years — a 1-year-old cat is roughly equivalent to a 15-year-old human, and a 2-year-old cat is about 24 in human years. After age 2, aging slows to roughly 4 human years per cat year. The AAHA/AAFP piecewise formula used in this calculator is far more accurate than simply multiplying by 7.