Pet math, done in seconds

Free calculators for pet owners: your dog's or cat's age in human years, how big your puppy will get, how much to feed, whether the chocolate your dog ate is dangerous, and how big a cage or tank your rat, hamster or snake needs. No sign-up, no app to install.

Dogs

Dog Age CalculatorYour dog's age in human years, by size, with the newer DNA formula too.Puppy Weight CalculatorEstimate your puppy's adult weight from its age and current weight.Dog Food CalculatorDaily calories and cups of food for your dog's weight and life stage.Dog Water Intake CalculatorHow much water your dog should drink a day, and when it is too much.Dog Pregnancy CalculatorYour dog's due date from the breeding date, with a week by week timeline.

Dog safety

Dog Chocolate Toxicity CalculatorHow dangerous is the chocolate your dog ate? Dose by weight and type.Can Dogs Eat It? Food CheckerSafe, careful or toxic: check 98 foods from grapes to peanut butter.Benadryl Dosage Calculator for DogsThe usual Benadryl (diphenhydramine) dose by weight, in tablets or liquid.

Cats

Cat Age CalculatorYour cat's age in human years and life stage, from the vet chart.Cat Food CalculatorDaily calories for your cat, split into cans of wet food and cups of dry.

Small pets, birds and reptiles

Pet Age CalculatorRabbit, hamster, rat, ferret, bird or reptile age in human years, with lifespans.Pet Gestation CalculatorDue date for cats, rabbits, guinea pigs, hamsters, rats, goats, horses and more.Small Pet Cage Size CalculatorMinimum cage or pen size for guinea pigs, rabbits, hamsters, gerbils, ferrets and more.Rat Cage CalculatorHow many rats fit in your cage, using the 2 cubic feet per rat rule.Reptile Tank Size CalculatorMinimum enclosure size for snakes, lizards, geckos, turtles and axolotls.

Fish and ponds

Aquarium CalculatorFish tank volume in gallons and liters, water weight, heater and filter size.Pond Volume CalculatorPond gallons for any shape, liner size, pump flow and how many fish fit.

Which calculator do I need?

QuestionCalculator
How old is my dog in human years?Dog age
How big will my puppy get?Puppy weight
How much should I feed my dog?Dog food
My dog ate chocolate: is it dangerous?Chocolate
Can my dog eat grapes, bananas or cheese?Can dogs eat
How much Benadryl can my dog have?Benadryl dose
When is my dog due?Dog due date
How much water should my dog drink?Water intake
How old is my cat in human years?Cat age
How much should I feed my cat?Cat food
How old is my rabbit, hamster or parrot in human years?Pet age
When will my rabbit, guinea pig or goat give birth?Gestation
How big a cage does my guinea pig, rabbit or hamster need?Cage size
How many rats fit in my cage?Rat cage
What size tank does my snake, gecko or bearded dragon need?Tank size
How many gallons is my aquarium?Aquarium
How many gallons is my pond?Pond volume

How we work out the numbers

Each calculator uses formulas and reference values that veterinarians use, such as the resting energy requirement for feeding, toxic doses from the Merck Veterinary Manual, and normal gestation lengths for each species. Every page shows the formula and its sources. The results are estimates for planning, not a diagnosis: your vet knows your pet.

Possible poisoning? Do not wait for symptoms. Call your vet, the ASPCA Animal Poison Control Center at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661.