How long do cats live?
The lifespan of a cat depends on many factors:
 breeds
 environments
 genetics
 diets
 sterilization
 lifestyle and care
All of the above factors affect your cat's lifespan. Cat's breed affects its lifespan. However, studies have shown that mixed breed cats are generally more robust and live longer than pure breed cats.
Sterilization can be a significant factor in your cat's lifespan. Sterilization eliminates the risk of developing diseases that may affect the cat's reproductive system in old age. Kittens live one to two years longer than cats.
Another important  and even the most important  factor that affects a cat's lifespan is its environment. Homeless and feral cats live up to three times shorter than domestic cats.
House cats are typically sterilized, vaccinated, and free from the stresses, risks, and dangers of the outside world. They are fed regularly and have easy access to fresh and clean water. The research shows that the average life expectancy of a domestic cat is 1420 years, which is about 17 years on average.
Homeless and feral cats live much shorter. The neighborhood in which it lives affects the life expectancy of a homeless cat. It is important whether he lives in the city or in the countryside, near roads or in a remote area, or near larger predators, whether he has a place to hide from the weather and whether there are more stray cats in the area. The factors limiting the life expectancy of a homeless cat are also increased exposure to fleas, ticks and other parasites and diseases. Outdoors, cats can also get into fights with other cats, leading to injury and scratching, and are at risk of accidents. The average life expectancy of a homeless cat is dramatically low and ranges from 3 to 11 years, which gives an average of about 7 years.
Curiosity
The longestlived cat was 38 years and 3 days (more than twice the life expectancy of this species). It was a Creme Puff female cat, who lived from August 3, 1967 to August 6, 2005. Her owner was Jake Perry, who also owned another longlived female cat  Granpa, a sphinx breed who died in 1998 at the age of 34 years and 2 months.
How to convert cat years into human years?
Of course, there is no single mathematical formula (or at least not a simple one), and there is no conversion factor that would be able to give 100% accuracy to the age of a particular cat in human years. Because there are too many factors influencing his life expectancy. Vitality is also important because not one adult cat can behave like a kitten.
Cat age does not have a linear curve compared to human age.
The conversion of a cat's age into human years is based on many studies and observations carried out by veterinarians.
As with many animals, a cat's 'childhood' and 'maturation' progress much faster than in humans. In the first two years of its life, a cat develops much faster than humans, and it can be assumed that one month of a cat's life corresponds to one year of human life. For example, a cat at 1 month is the equivalent of a oneyearold baby, a cat at 2 years old is a man at 24. After 2 years, the cat's age is calculated on average so that one year of a cat's life equals 4 human years.
Below is a table of cat age conversion into human years, also used in our cat age calculator
.

CAT AGE 
HUMAN AGE 
LIFE STAGE 

1 month 
1 
baby 
2 months 
3 
3 months 
4 
4 months 
8 
5 months 
9 
6 months 
10 

7 months 
11 
child 
8 months 
11 
9 months 
12 
10 months 
13 
11 months 
14 
12 months 
15 
13 months 
16 
14 months 
17 
15 months 
17 
16 months 
18 
17 months 
19 
18 months 
20 
19 months 
20 
20 months 
21 
21 months 
22 
22 months 
23 
23 months 
23 
2 years 
24 

3 years 
28 
young 
4 years 
32 
5 years 
36 
6 years 
40 

7 years 
44 
adult 
8 years 
48 
9 years 
52 
10 years 
56 

11 years 
60 
old 
12 years 
64 
13 years 
68 
14 years 
72 

15 years 
76 
venerable 
16 years 
80 
17 years 
84 
18 years 
88 
19 years 
92 
20 years 
96 

21 years 
100 
longlived 
22 years 
104 
23 years 
108 
24 years 
112 
25 years 
116 