I have seen charts but not a way to calculate it so here is the current formula. Cat are considered matured when they turn 2 years old. For any of you who have adopted a 1 year old cat, you know that you still have a big teenager on your hands. At 2 years old, a cat’s age is close to 22 human years. OK, he can have catnip now! At this age, a cat in a multi-cat household has to decide if it wants to “move up the ladder” in the household and there can be some sparks for several months until this decision gets worked out. Jim and I have 2 brothers who are 12 now but when they turned 2 years old, they had to make a decision about which one would be the #1 can and which would be #2. They are normally the best of friends but for several months, it was very tense between them until the smaller boy, Max, convinced his brother that he was the one for the top dog spot. Social order is very important in the cat world but I can save this topic for another blog.
Anyway, on to the formula- for every year after 2 years old, add 4 human years. If you have a cat that is 7 years old, he is 44 in human years (22+ 5 years x 4). An 18 year old cat is the equivalent of an 86 year old human (22+ 16 x 4).
A cat is considered a “senior” when they turn 10-12 years old. As your cat approaches “senior” status, consider changing your yearly veterinarian appointments to twice a year. I think it is better to catch something early as your cat ages rather than find out too late. I would also recommend having a baseline blood panel done to check for diabetes, thyroid, kidney and liver function. This way you have a better idea of what is going on as your cat ages. We all know that cats are masters at hiding pain and discomfort so best to keep on top of your cat’s health. Certainly, any change in behavior is a signal for a visit to your veterinarian. Loss of appetite, lethargy, not using the litter box, any discharge from anywhere, or a change in behavior are some of the signs of a health issue. Jim and I almost lost Max’s brother, Danny, earlier this year and it happened so suddenly. Our cats have the run of the screened lanai all day but when the sunlight fades, it is time for them to come in. Always easy to usher in, Danny just laid on the tile with his paws tucked under him and would not move. We rushed him to the emergency clinic where he was treated for congestive heart failure. He responded well to the treatment and ongoing drug therapy and almost a year later is doing just fine- good enough to chase one of our other cats around the house! I know if we had not noticed or reacted so quickly that Danny may not have been able to recover. Our advice is to know your cats behavior and what ever you do, do not wait if something is wrong with your cat.