Cat Years to Human Years Calculator

Want to turn cat years into human years? Enter your cat’s age (or birthday) below. You’ll get their age in human years, their life stage, the dates of their next big milestones and a share card with their name on it. Add your own age too if you want to see who’s “older”. Quick answer: a 1-year-old cat is about 15 in human years, a 2-year-old is about 24, and each year after that adds roughly 4.

How do cat years work?

Cats grow up fast. In their first year they go from a helpless newborn to a young adult who can have kittens of their own. That’s a lot of living, so the first year counts as about 15 human years. The second year adds about 9 more, which puts a 2-year-old cat at roughly 24.

After that things slow down. Each extra cat year is worth about 4 human years. So a 5-year-old cat is around 36, a 10-year-old is around 56, and a 15-year-old is in their mid-70s.

You may have heard “multiply by 7.” That old rule came from dogs, and it doesn’t fit cats. (It doesn’t fit dogs very well either. Our dog years calculator goes by size.) It makes young cats seem far younger than they are and old cats seem older.

Cat age chart: cat years to human years

This cat age chart follows the International Cat Care scale. The life stage column uses the AAHA/AAFP feline life stages that vets use. You can print it for the fridge or embed it on your own site.

Cat life stages and what they mean for care

Vets group cats into four life stages. Each one comes with its own things to watch for.

• Kitten (birth to 1 year). Rapid growth, vaccines, spay or neuter, and lots of social play. Feed a kitten food.
• Young adult (1 to 6 years). Usually the healthiest years. This is when weight tends to creep up, so keep an eye on portions.
• Mature adult (7 to 10 years). Roughly middle age in human terms. Dental disease and extra weight are common now.
• Senior (11 years and up). Kidney disease, an overactive thyroid, arthritis and diabetes become more likely. Many vets want to see senior cats more often than once a year.

Cats hide pain and illness well. A change in thirst, appetite, weight or litter box habits in an older cat is worth a vet visit, even if they seem fine otherwise. Our cat weight chart can help you spot weight changes early.

Got more than one cat? Compare them

Enter up to four cats to see who’s oldest in human years and which life stage each one is in. Handy for multi-cat homes, and a fun one for siblings adopted at different ages.

Human years to cat years

Going the other way works the same, just backwards. Up to 24 human years, cats cover ground fast: 15 human years is a 1-year-old cat and 24 is a 2-year-old. Past that, every 4 human years equals one cat year. So a 40-year-old person lines up with a 6-year-old cat, and a 60-year-old lines up with an 11-year-old cat. Pick “Human years to cat years” in the calculator to try any age.

Do indoor and outdoor cats age differently?

Some calculators add extra years for outdoor cats. We don’t, because there’s no agreed formula for it. The cat years scale describes how fast cats mature, and that’s the same indoors or out. What does differ is risk. Outdoor cats face traffic, fights, parasites and more infections, so on average they don’t live as long. If your cat goes outside, keeping up with vaccines, parasite control and yearly checkups matters even more.

Why do other charts give slightly different numbers?

Nearly every chart agrees on the first two years: about 15, then about 24. After that most vets and cat charities, including International Cat Care, add 4 human years per cat year. A few charts slow the count down to 2 years per year once a cat passes 15, so they’ll show a 20-year-old cat as a little younger than we do. Neither is exact. Cats age as individuals, and your vet’s view of your cat’s health counts for more than any chart.

How to tell a cat’s age if you don’t know it

Adopted a cat with no birth record? You can’t pin down an exact age by looking, but there are clues:

• Teeth. Kittens have all their adult teeth by around 6 months. Yellowing and tartar tend to build up with age.
• Eyes. Young cats have clear, bright eyes. Older cats often develop a slight cloudiness in the lens.
• Coat and body. Seniors may have a coarser coat, a few gray hairs and less muscle along the spine and back legs.
• Behavior. Kittens and young adults play hard. Older cats sleep more and may be stiff when they get up.

Your vet can give the best estimate. Once you have a rough age, use the birthday option above with an estimated date.

Frequently asked questions

More free pet calculators