Pet math, done right.

Every calculator on this site uses published veterinary formulas — size-adjusted dog aging, RER/MER calorie math, real toxicity thresholds. No guesswork, no sign-up, just answers.

Dog Calculators

Dog Age CalculatorConvert dog years to human years, adjusted for breed size.Puppy Weight CalculatorEstimate your puppy's adult weight from its age and current weight.Dog Calorie CalculatorDaily calories your dog needs, using the veterinary RER/MER formula.Dog Food CalculatorTurn calorie needs into cups of food per day, from your bag's kcal/cup.Chocolate Toxicity CalculatorMy dog ate chocolate — how serious is it? Check the risk level now.Dog Ideal Weight CalculatorBody condition score to target weight, plus safe weight-loss calories.Raw Dog Food CalculatorDaily BARF portions with the 80/10/10 breakdown, by body weight.Dog Water Intake CalculatorHow much water your dog should drink every day.Dog Walking Calorie CalculatorCalories your dog actually burns on a walk.Dog Pregnancy CalculatorDue date and week-by-week milestones from the mating date.Dog Heat Cycle CalculatorPredict the next heat and the fertile window.Dog Crate Size CalculatorMeasure your dog, get the right standard crate size.

Cat Calculators

Cat Age CalculatorConvert cat years to human years with the veterinary age chart.Cat Calorie CalculatorDaily calorie needs for cats and kittens, vet RER formula.Cat Food CalculatorWet and dry food portions per day, from your cat's calorie needs.Kitten Growth ChartIs my kitten's weight on track? Check against the weekly curve.Toxic Food Checker for CatsInstantly check if a food is dangerous for your cat.Cat Water Intake CalculatorHow much your cat should drink — and how diet changes it.Cat Pregnancy CalculatorDue date and kitten timeline from the mating date.

Small Pet Calculators

Rabbit Age CalculatorRabbit years to human years, with life-stage guide.Guinea Pig Age CalculatorGuinea pig years to human years.Hamster Age CalculatorHamster age in human years — they live fast.Bird Age CalculatorParrot and pet bird age in human years, by species.Horse Age CalculatorHorse years to human years with the equine aging chart.Turtle Age CalculatorTurtle and tortoise age in human years, by species.

Why these calculators are different

Most pet calculators online use oversimplified rules — the infamous "multiply by 7" for dog years, or one-size-fits-all feeding charts. FurCalcs is built on the formulas veterinary professionals actually use: AKC size-adjusted aging curves, the RER/MER energy equations from veterinary nutrition, and toxicity thresholds from the Merck Veterinary Manual. Each tool explains its formula and sources, so you can check our math.

Nothing here replaces your veterinarian — but for the everyday questions ("how old is my dog really?", "how much should she eat?", "he ate a brownie, do I panic?"), you'll get an honest, well-sourced starting point in seconds.