How do you Calculate a Cats age to Human years?

I know for Dogs it's seven Dog years to one Human year. What about Cats? Is there a way to make the same Comparison?
Answers:
It's not a simple linear comparison (and it isn't for dogs, either.) That's because they develop so rapidly in their first year or two.

At one year of age a cat is about like a human of fifteen: approaching adult size but still has some growing to do; sexually mature and able to breed, but emotionally not really ready for effective parenthood.

At age two they're established in young adulthood, about like a human of twenty-three.

After that they age about four times as fast as we do.

This comes from the Cornell Feline Health Center:

Cat = Human
1 = 15
2 = 23
3 = 27
4 = 31
5 = 35
6 = 39
7 = 43
8 = 47
9 = 51
10 = 55 (the ages at which we're considered "seniors")
11 = 59
12 = 63
13 = 67
14 = 71
15 = 75
16 = 79
17 = 83
18 = 87
19 = 91
20 = 95
21 = 99
22 = 103

The normal life expectancy of the domestic cat is about seventeen. Twenty is no longer really rare.

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i'm pretty sure its the same. maybe like 5 years tho instead of 7
cuz most cats live to be around 15

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It's a little bit less.like between 6 and 7 years, but for all practical purposes I've just used 7.

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here is the best way

http://cats.about.com/cs/healthissues/a/.

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http://www.blakjak.demon.co.uk/cat_yrs.h.

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At one year it is 16, two years is 21, three, 25.

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1human year 6 cat years
2 human years 13 cat years
3 human years 18 cat years
4 human years 23 cat years
5 human years 30 cat years
6 human years 40 cat years
7human years 45 cat years

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http://www.juliagreen.com/cat.asp.

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go to catage.com and take the little survey they have there. it's free, easy, and a lot of fun. it takes your cat's actual age, and calculates how old it really is in human years based on how it's living, it's personality, all kinds of stuff. i did it with my 13 year old kitty, and he's 62 in people years.