Aging Charts

Aging Chart for Dogs
Comparative Age

Dog
Human
6 months 5-6 years
8 months 9-10 years
1 year 14-15 years
2 years 22-24 years
3 28
4 32
5 36
6 40
7 44
8 48
9 52
10 56
11 60
12 64
13 68
14 72
15 76
16 80
17 84
18 88
19 92
20 96
21 100
22 104
23 108
   
   

Comments:

This aging chart would be most appropriate for dogs less than 20-22 lbs (or 9-10 kgs) of body weight. 

Also, since they do not tend to live as long as the smaller breeds, for larger size and weight dogs, the relative aging compared to humans varies more substantially (especially in the giant breeds).

For a comparison, please reference Dr. Fred Metzger's "Dog Age Chart" (Courtesy of Pfizer Animal Health) or FPSi's "Dog Years" chart (Specialist in French property).

Aging Chart for Cats
Comparative Age

Dog
Human
6 months 9-10 years
8 months 12-13 years
1 year 15 years
2 years 24 years
3 32
4 36
5 40
6 44
7 48
8 52
9 56
10 60
11 64
12 68
13 72
14 76
15 80
16 84.5
17 89
18 93.5
19 98
20 101
21 104
22 107
23 110
24 113
25 116

Comments:

Cats tend to age more similarly to small dogs. 

Yet, it is much more common to see a cat older than 20 years old than it would be for a comparably sized dog.  So, if we really want to compare cat aging to human aging, and 100 years old is the template, we should use a chart similar to what is shown/estimated above.