Most people think that calculating the age of dogs and cats in "human years" is quite simple: multiply their age by seven. For example, a 4-year-old dog or cat would actually be 28 years old in human years. But when you really begin weighing out the arithmetic, this method doesn’t add up. Say a 1-year-old dog is the equivalent of a 7-year-old human — get out of here! How many 7-year-old humans are sexually active and capable of reproducing? Dogs and cats are much more likely to have babies at 1 year old or even at 10 years old, than any person who is 7 or 70.

Many veterinarians now agree that a pretty good guess on the age of pets can be made using the following formulas for dogs and cats.

DOGS
Aging is much faster during a dog’s first two years but varies among breeds. Large breeds, while they mature quicker, tend to live shorter lives. By the time they reach 5 they are considered "senior" dogs. Medium-sized breeds take around seven years to reach the senior stage, while small and toy breeds do not become seniors until around 10  or older. 

But with all the vitamins, probiotics, stomach enzymes, better food (raw or home-cooked) or at least natural and organic pet foods that pets are now eating plus the fact that many live inside out of the elements and are pampered, pet age is increasing. So while many veterinarians agree that a pretty good guess on the age of pets can be made using the following formulas for dogs (and cats), the average is changing daily.

So, A Dog’s Life Can be Longer Than You Think…

Pictured: Two of the oldest dogs on record – #1 Bramble at age 27 (Died at age 27, 211 days) and #2 Bella at age 26 (Died at age 29, 193 days)

Although still simple, it is much more accurate than the seven-year method. (Use these as a guestimate and guide.  More and more pampered dogs are living an additional 3 to 5 years over the top averages, or even longer)

Assume that a 1-year-old dog is equal to a 12-year-old human and a 2-year-old dog is equal to a 24-year old human. Then add four years for every year after that. (Example: A 4-year-old dog would be 32 in human years.) Since this method takes into consideration the maturity rate at the beginning of a dog’s life and also the slowing of the aging process in his later years, Martha Smith, director of veterinary services at Boston’s Animal Rescue League, feels that this is the more accurate calculation formula.

Here is a chart, for easy reference:

A dog’s average lifespan is around 12 or 13 years, but again, this varies widely by breed. The larger your dog is, the less time it will live. Female dogs tend to live a little longer. (Great Danes only live between 7 and 12 years.)

Wikipedia: List of Oldest (Known) Dogs

CATS
Now let’s take a glimpse at a simple formula for calculating feline age in human years. Assume that a 1-year-old cat is equal to a 15-year-old human and a 2-year-old cat is equal to a 24-year-old human. Then add four years for every year after that. (Example: A 4-year-old cat would be 32 in human years.)

The following chart shows this formula of calculation:

Check out this and more great stuff from PetsAdviser.com and WebVet.com:

Pictured:  Lucy at age 39 (still alive)  -  Oldest Living Cat on Record

What’s her secret? It must be something in the Fancy Feast.

Lucy, from Llanelli, South Wales, is a proud Gen X’er – in her time, she’s lived through eight prime ministers, a handful of wars, and the rise of the technological generation. But the years take a toll, and at 39-years-old, Lucy’s gone deaf and probably has a bit of trouble getting up in the morning. But that’s all excusable when you consider Lucy is a feline.

The only other cat who comes close to her age was Creme Puff, a Texas cat who died at 38 years and three days.

And when you see 29-year-old dogs and 39-year-old cats, you realize that the charts are really only guestimates.

Related: Top 5 Ways to Improve Life for Your Senior Dog

How Long are Cats Supposed to Sleep?

The Truth About Cats’ Nine Lives

Dog TV: Programming for Your Pup

How to Safely Remove Fleas from Kittens

h/t to Gayle Hickman  -  Yahoo.com – h/t to MJ