The KittyCorner cat age calculator

Our cat age calculator estimates your cat’s age in human years based on its breed, size, and age.

Below is some information about how we make our calculations.

If you want to go straight to the calculator, then scroll down or click here.

Our cat age calculator formula

The calculation follows a formula where the first year of a cat’s life is equivalent to 15 human years, the second year is equivalent to 9 more human years, and each year after that is considered 4 human years.

Breed factors

The calculator also considers the breed and size of your cat when estimating its age in human years. Some breeds, such as Siamese and Sphynx, tend to have longer lifespans, so the calculator adjusts the result to reflect a slightly younger human age equivalent. This means that a cat of these breeds may have more years left to live compared to a human of the same age.

On the other hand, breeds like Maine Coon and Ragdoll typically have shorter lifespans, so the calculator adjusts the result to reflect a slightly older human age equivalent.

Similarly, smaller cats are estimated to have a slightly younger human age equivalent compared to larger cats, as they tend to have longer lifespans.

Example 1:

Below is a simple explanation of how the cat age calculator works for a 5-year-old Siamese cat weighing 6 pounds.

First, the calculator starts with a base age of 24 years for a 2-year-old cat.

Then, it adds 4 human years for each additional cat year after 2. So, for a 5-year-old cat, it adds 12 human years (3 x 4) to the base age of 24, giving a starting point of 36 human years.

Next, the calculator adjusts this age based on the Siamese breed factor of 0.83 (see chart below) and the small size factor of 0.9 for a 6-pound cat (see chart below).

It multiplies 36 by 0.83 and then by 0.9, resulting in a final estimated human age of about 27 years old for your 5-year-old Siamese cat.

Example 2:

Let’s instead assume that our 5-year-old cat is a Manx weighing 15 pounds.

As before, the calculator starts with a base age of 24 years for a 2-year-old cat and adds 4 human years for each additional cat year after 2.

Again, for a 5-year-old cat, it adds 12 human years (3 x 4) to the base age of 24, giving a starting point of 36 human years.

Now, the calculator adjusts this age based on the Manx breed factor of 1.32 and the large size factor of 1.1 for a 15-pound cat.

It multiplies 36 by 1.32 and then by 1.1, resulting in a final estimated human age of about 52 years old for your 5-year-old, 15-pound Manx cat.

Big difference, right? That heavyset Manx cat is almost twice as “old” in human years as the slim SIamese cat.

Size Weighting Factors:

Smaller cats tend to live a bit longer than older cats, so we multiply by 0.9 for small cats, 1.0 for medium-sized cats, and 1.1 for larger cats.

• Small (5 to 8 pounds / 2.3 to 3.6 kg): 0.9
• Medium (9 to 12 pounds / 4.1 to 5.4 kg): 1.0
• Large (13 to 20 pounds / 5.9 to 9.1 kg): 1.1

The KittyCorner Age Calculator

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The breed weightings used in the calculator

To calculate the breed weightings, we divided the average lifespan of that breed by the midpoint of the lifespan range for each breed. This ensures that breeds with longer lifespans have a multiplier-factor less than 1 (adjusting the human age equivalent to be younger), while breeds with shorter average lifespans have a multiplier-factor greater than 1 (adjusting the human age equivalent to be older).

Breed	Lifespan (Years)	Weighted Value
Abyssinian	9-15	1.21
American Bobtail	13-15	1.03
American Curl	15+	0.97
American Shorthair	15-20	0.83
American Wirehair	7-12	1.52
Australian Mist	14-19	0.88
Balinese	18-22	0.72
Bengal	12-16	1.03
Birman	12-16	1.03
Blue Chartreux	12-15	1.08
Bombay	15-20	0.83
British Shorthair	12+	1.11
Burmese	16-18	0.85
Burmilla	10-15	1.16
California Spangled	9-16	1.16
Ceylon	Less Than 15	1.11
Chantilly-Tiffany	14-16	0.97
Colorpoint Shorthair	9-16	1.16
Cornish Rex	11-15	1.11
Cymric	8-14	1.32
Devon Rex	9-15	1.21
Domestic	12-14	1.11
Egyptian Mau	13-16	1.00
European Shorthair	15-22	0.78
Exotic Shorthair	12-14	1.11
German Rex	10-14	1.21
Havana Brown	12-15	1.08
Himalayan	15+	0.97
Japanese Bobtail	15-18	0.88
Javanese	10-15	1.16
Korat	15+	0.97
LaPerm	10-15	1.16
Maine Coon	12-15	1.08
Manx	8-14	1.32
Munchkin	12-14	1.11
Nebelung	15-18	0.88
Norwegian Forest	14-16	0.97
Ocicat	12-15	1.08
Oriental	12-15	1.08
Persian	15+	0.97
Pixiebob	Less Than 12	1.32
Ragdoll	12-17	1.00
Russian Blue	15-20	0.83
Scottish Fold	Less Than 15	1.11
Selkirk Rex	12-15	1.08
Siamese	15-20	0.83
Siberian	11-15	1.11
Singapura	9-15	1.21
Snowshoe	12-15	1.08
Sokoke	9-15	1.21
Somali	10-12	1.32
Sphynx	13-15	1.03
Tonkinese	12-16	1.03
Turkish Angora	12-18	0.97
Turkish Van	12-17	1.00
Other	–	1.00

Oldest Cats of All Time

Creme Puff from Austin, Texas, holds the Guinness World Record for the oldest cat, living an impressive 38 years and 3 days from August 3, 1967, to August 6, 2005.

Baby, a black domestic short-haired cat from Duluth, Minnesota, lived to be 38 years old, passing away in March 2008. She was recognized by her owner as one of the oldest cats.

Puss from Devon, England, reportedly lived to be 36 years old, from 1903 to 1939. Puss was documented by the Guinness World Records before Creme Puff took the title.

Granpa Rexs Allen, a Sphynx-Devon Rex cross, lived to be 34 years and 2 months old. Owned by the same person who owned Creme Puff, Granpa was recognized by the Guinness World Records.

Sarah, a tabby cat from New Zealand, lived to be 33 years old, passing away in 2015. Her age was confirmed by her vet, making her one of the oldest documented cats in the world.

Sasha from the UK, lived to be 32 years and 8 months old. Sasha’s remarkable lifespan was recognized by her local community and her loving owner.

Mischief from the UK, lived to the age of 31 years. She was well known in her local area for her longevity and the affectionate care given by her owner.

Rubble, a Maine Coon from Exeter, England, lived to be 31 years old. He celebrated his milestone birthdays with special treats and attention from his owner.

Nutmeg from Tyne and Wear, UK, lived to be 31 years old. He was adopted as a stray and given a loving home, where he thrived for many years.

Scooter, a Siamese cat from Mansfield, Texas, lived to be 30 years old. He was recognized by the Guinness World Records in 2016, shortly before his passing.