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Dog and cat calculators you can check
How old is your dog in human years? How much should your cat eat? When are the puppies due? Every answer here comes with its formula, worked examples and the veterinary sources it is based on, so you can see exactly where the number comes from.
- 23 calculators
- 38 cited sources
- 28 publishers
- Sources checked October 25, 2026
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How old is your dog in human years?
Dogs age fastest in their first two years. After that the pace depends on size: on the AKC chart, the bigger the dog, the more human years each birthday adds. Pick a size and an age to read it off the chart.
Open the full dog age calculator, with the newer epigenetic formula side by side.
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Dog calculators
- Dog age in human yearsTwo methods side by side: the size-based chart and the 16·ln(age)+31 epigenetic formula.
- Dog food and caloriesDaily calories from weight and life stage, then cups per day from your food's kcal per cup.
- Dog water intakeTypical daily water by weight, and the level at which drinking is considered excessive.
- Dog pregnancy due dateDue date window from the breeding date, LH surge or start of diestrus.
- Dog ideal weight (BCS)Rough ideal weight from current weight and the 9-point body condition score.
- Yearly cost of a dogYearly and first-year cost, starting from ASPCA estimates you can change.
- How long do dogs live?Average life expectancy by adult size (US) and median lifespan for 143 breeds (UK).
- Puppy weight calculatorEstimated adult weight from age and weight today, on published breed growth curves.
- How much to feed a puppyCalories, cups and meals per day for a growing puppy, from weight and age.
- Dog heat cycle calculatorNext heat window and average stage dates from the start of her last heat.
- Dog crate sizeCrate interior size from your dog's length and height, for home or air travel.
- Raw dog food calculatorDaily amount of a raw food from your dog's calorie needs and the label, plus safety facts.
- Dog pregnancy week by weekDated milestones from breeding to whelping: tests, X-rays, due window, labor.
Cat calculators
- Cat age in human yearsHuman-year equivalent from the International Cat Care chart, plus the AAFP/AAHA life stage.
- Cat food and caloriesDaily calories from weight and life stage, then cups per day from your food's kcal per cup.
- Cat pregnancy due dateDue date window from the mating date, with the usual and the full observed range.
- Cat ideal weight (BCS)Rough ideal weight from current weight and the 9-point body condition score.
- Yearly cost of a catYearly and first-year cost, starting from ASPCA estimates you can change.
- How long do cats live?Average life expectancy by sex and type (US) and by breed (UK).
- How much to feed a kittenDaily calories and cups for a growing kitten, from its weight today.
- Kitten and cat weight chartNormal kitten weights for weeks 1–8, age from weight, and typical adult cat weight.
- Cat heat cycle calculatorWhen this heat should end and when the next one is due, from its first day.
- How many litter boxes?Number of boxes for your cats and floors, and the minimum box size.
Method
How these calculators work
- Published methods only. Formulas and reference values come from veterinary associations (AVMA, AAHA, WSAVA), the Merck Veterinary Manual, the ASPCA and peer-reviewed studies. Each page lists its sources and when we last checked them.
- Estimates, not diagnoses. A formula works on averages. Your veterinarian can examine your pet; we can't.
- Private by design. The math runs in your browser. Nothing you type is sent to us.