Free pet calculators built on published veterinary formulas
Pet math your vet would recognize
Petculate takes the formulas vets actually use (WSAVA energy requirements, size-adjusted age charts, the UCSD epigenetic clock) and turns them into fast, free calculators. Every number has a source. Nobody asks for your email.
Calculators
- Dog Age Calculator Dog years to human years with the size-adjusted chart plus the epigenetic formula.
- Cat Age Calculator Cat years to human years with the AAHA/AAFP life-stage convention.
- Dog Calorie Calculator Daily kcal target from the RER formula and WSAVA life-stage factors.
- Dog Food Calculator Cups per day and per meal of your specific food, from the bag's kcal/cup.
- Puppy Feeding Chart Printable growth-stage chart plus a portion calculator by age and weight.
- Raw Dog Food Calculator Percent-of-body-weight raw portions, with the safety context included.
- Cat Calorie Calculator Daily kcal for cats and kittens, plus cans per day of your food.
How the calculators work
The feeding tools start with the Resting Energy Requirement, which is 70 × kg0.75, then apply the WSAVA life-stage multipliers. The age tools use the American Kennel Club's size-adjusted chart. For dogs we also show the 2020 UC San Diego epigenetic formula as a second opinion, clearly labeled. The methodology page lists every formula with its source and its blind spots, because a calculator you can't audit is just a guess with a nice font.
These are estimates, not veterinary advice. Animals vary and your vet has the final word. New here? Start with the feeding guide or the story behind dog years.
Which feeding tool do you need?
The feeding calculators answer different questions. The calorie calculator tells you how much energy your dog needs each day. The food calculator turns that into cups of the food you actually buy, using the kcal/cup number printed on the bag. The puppy chart covers the growth months, when portions change every few weeks and meal timing matters as much as amount. If you feed raw, the raw calculator lays out the safety debate right next to the math.
Cats get their own version: the cat calorie calculator runs the same RER math with feline factors and converts the target into cans of wet food.
The age tools are simpler. Dogs need a size class, since a Great Dane ages almost twice as fast as a Chihuahua after year two. Cats follow one curve.