About Cat Calculators
Free, accurate, vet-informed calculators for every stage of your cat’s life — built by a cat owner who got tired of searching for simple answers.
Why I Built This Site
My name is Olivia Smith. I have kept cats my whole life — right now I share my home with two, a tabby named Biscuit and a senior tortoiseshell called Mabel who is eleven and requires considerably more looking after than she did a few years ago.
A few years ago I found myself in a frustrating situation. Mabel had started losing a little weight and I wanted to understand her calorie needs better. I looked online and found either extremely technical veterinary literature that required a science degree to follow, or breezy blog posts that gave the same generic numbers regardless of the cat’s weight, age, or diet.
I knew the RER formula existed. I knew that a senior cat on wet food had completely different water and calorie needs from a kitten on dry kibble. But nowhere could I find a single calculator that took all of that into account and gave me a real number I could actually use.
So I decided to build it myself. And then one calculator became two, and two became eight, and somewhere along the way Cat Calculators became a proper resource.
Every calculator on this site started as a question I had about one of my own cats. Every piece of content is written the way I wish someone had explained it to me: in plain English, based on real veterinary sources, without padding or waffle.
What Makes Our Calculators Different
Most cat calculators online give you a number and nothing else. We build ours to actually explain the result so you understand what it means and what to do with it.
Every calculator on this site uses verified veterinary formulas. The calorie calculators use the RER formula endorsed by the WSAVA and the American College of Veterinary Nutrition. The pregnancy calculator uses the 63 to 65 day gestation standard cited by PetMD and reviewed veterinarians. The growth calculator uses the 16-week landmark validated by WALTHAM across thousands of domestic cats.
We do not make up numbers. We do not average things out and round to the nearest ten. We cite our sources on every calculator page so you can check the underlying science yourself.
Our Calculators
Cat Calculators covers the full range of practical questions cat owners ask — from “how old is my cat in human years” to “how much should I feed my senior CKD cat on a wet diet.” Here is what is currently live on the site.