How can you tell how old a cat is? This question comes up for anyone who rescues a stray or adopts a cat from a shelter. What signs can help you figure out a cat’s age, and how old is that in human years? You’ll find the answers in this article.
How to Tell a Cat’s Age
By Its Teeth
Teeth are one of the best clues to a cat’s age, and they work best for kittens. Vets most often use them to estimate how old an animal is.
- If a kitten has only its first baby incisors, it’s about 2–4 weeks old.
- If baby canine teeth have appeared next to the incisors, the kitten is about 3–4 weeks old.
- Baby premolars mean the kitten is about 4–6 weeks old.
- If the baby teeth are being replaced by permanent ones (starting with the incisors), the kitten is about 3–4 months old.
- A full set of white, healthy permanent teeth (usually by 6–7 months) points to an age of about 6 months to 1 year. There should be no tartar or signs of wear.
- Slight yellowing of the enamel and a little wear on the middle lower incisors suggest an age of about 2 years.
- Tartar on all the teeth and wear on the central upper incisors suggest an age of about 3–5 years.
- Uneven enamel color and worn outer upper incisors suggest an age of about 6–7 years.
- Heavily yellowed, worn teeth and some missing teeth suggest a cat older than 10.
- Missing canines are a sign of old age: about 15 years or more.
Keep in mind that teeth aren’t a perfectly accurate guide to age. A cat’s teeth can be in poor shape because of a lack of dental care, or, on the other hand, sparkling teeth might mislead you and simply reflect excellent care.
By Sexual Maturity
If your male cat starts marking his territory with strong-smelling urine, he has reached sexual maturity (usually at around 5–6 months old). Females that have reached maturity go into heat, usually between about 4 and 12 months old: they become extra affectionate, roll around and yowl loudly to attract males.
By Its Coat
Younger cats have soft, fine fur. With age, the coat becomes coarser, and the color may get lighter or darker. Like people, older cats can go gray: you may see individual white or gray hairs, or even whole patches. Senior cats may also groom less, so their coat can look duller or a little unkempt.
By Its Eyes
Young cats usually have bright, clear eyes. With age, you may notice changes in eye color, cloudiness or patchy pigment on the iris. From middle age, the lens of the eye slowly becomes denser and can take on a slightly hazy, bluish look (a normal change called lenticular sclerosis). A vet can see the early stages with an ophthalmoscope; in cats over 10, it’s often visible to the naked eye. In older cats, the iris can also start to look thinner and lacy.
By Its Body
Aging affects the whole body. Here’s what your cat’s body can tell you:
- young cats are usually more muscular and lean because they’re more active;
- middle-aged cats tend to be rounder and heavier, but you can still feel firm muscle underneath;
- senior cats often lose muscle, so their shoulder blades and spine become more prominent, and their skin can become less elastic.
By Its Behavior
Activity level and daily routine (when your cat sleeps and when it’s awake) can also hint at its approximate age. Watch your cat closely. Behavioral signs of age include:
- Young cats are usually more playful and curious. Their naps alternate with long periods of activity.
- Middle-aged cats are still interested in the world but behave more calmly and cautiously.
- Older cats are less active and sleep most of the time. They may mix up day and night and become more vocal at night.
- Fearfulness, anxiety and irritability are more common in senior cats, sometimes because of pain or cognitive changes, so mention them to your vet.
Cat Years to Human Years
Cats grow up fast. A year after they’re born, they’re fully developed and sexually mature, so compared with humans, a cat’s childhood is very short.
There are several charts online that convert cat years to human years. The one below is based on the widely used conversion from the American Association of Feline Practitioners and International Cat Care: a cat’s first year equals about 15 human years, the second year adds about 9 more, and each year after that equals about 4 human years.
| Cat’s age | Human equivalent |
|---|---|
| 1 month | about 1 year |
| 3 months | about 4 years |
| 6 months | about 10 years |
| 1 year | 15 years |
| 2 years | 24 years |
| 3 years | 28 years |
| 4 years | 32 years |
| 5 years | 36 years |
| 6 years | 40 years |
| 7 years | 44 years |
| 8 years | 48 years |
| 9 years | 52 years |
| 10 years | 56 years |
| 11 years | 60 years |
| 12 years | 64 years |
| 13 years | 68 years |
| 14 years | 72 years |
| 15 years | 76 years |
| 16 years | 80 years |
| 17 years | 84 years |
| 18 years | 88 years |
| 19 years | 92 years |
| 20 years | 96 years |
Vets also divide a cat’s life into life stages: kitten (up to 1 year), young adult (1–6 years), mature adult (7–10 years) and senior (over 10 years). Senior cats benefit from vet checkups every 6 months.
What Affects a Cat’s Lifespan
Many factors affect how long your cat lives: genetics and quality of life, including diet and overall care. Cats are living longer than ever, and today most pet cats live about 12–18 years, with many reaching their 20s. Read more in our article How Long Do Cats Live?
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