How old is your dog, really?
Friendly, vet-informed calculators for dogs, cats, and fish — clear answers on age, weight, feeding, and more in seconds. No signup, nothing stored.
Featured tool
Try the dog age calculator right here — edit the numbers and the result panel updates as you go. Open the full page for the worked example and FAQ.
The calculators
Pick a tool and get a clear answer — no jargon, just helpful pet math.
Dog Age Calculator
Convert your dog's age to human years, adjusted for size.
Open calculatorCat Age Calculator
Translate your cat's age into human years by life stage.
Open calculatorPuppy Weight Predictor
Estimate your puppy's adult weight from its current age.
Open calculatorDog Food Calculator
Daily cups of food from weight, age, and activity level.
Open calculatorDog Calorie Calculator
Daily calorie needs (RER/MER) for your dog.
Open calculatorCat Food Calculator
How much to feed your cat per day, by weight and life stage.
Open calculatorDog Pregnancy Calculator
Whelping due date and week-by-week from the breeding date.
Open calculatorDog Crate Size Calculator
The right crate dimensions from your dog's measurements.
Open calculatorDog Water Intake
How much water your dog should drink each day.
Open calculatorFish Tank Volume
Aquarium volume in gallons or liters from the tank size.
Open calculatorLitter Box Calculator
How many litter boxes and how much litter per month.
Open calculatorDog Walk & Exercise
Daily exercise minutes your dog needs, by breed and age.
Open calculatorWhy pet owners use CritterCalc
Pet questions rarely have a single number attached — "how old is she in human years?", "how much should I feed him?", "what size crate?" CritterCalc answers them with clear, source-backed math for dogs, cats, and fish, in seconds.
- Instant & private: everything runs in your browser; nothing you type is stored or sent.
- Source-backed: feeding and age tools use published veterinary and AAFCO/NRC formulas, with a cited source on every page.
- Not a vet: these are helpful estimates — for medical or dosing questions, always see your veterinarian.