Pet Calculators
Free pet calculators for dog age, cat age in human years, and daily calorie needs for cats. Simple, vet-informed tools for dog and cat owners.
Pet Calculators - Understand Your Dog and Cat in Human Terms
Dogs and cats age far faster than we do, and their calorie needs are nothing like ours. These calculators translate a pet’s years into human-equivalent age and estimate how much a cat should eat each day, using the same size-based and metabolic formulas that veterinary guidance relies on.
Seven Pet Calculators
Dog Age Calculator - Converts a dog’s age into human years using a size-aware model. The first year counts as about 15 human years, the second adds 9 more, and every year after that adds 4 to 7 human years depending on whether your dog is small, medium, large, or giant. Larger breeds age faster in later life.
Cat Age Calculator - Converts a cat’s age into human years. The first year is roughly 15 human years, the second reaches about 24, and each additional year adds 4 human years. A 5-year-old cat is about 36 in human terms, and a 15-year-old cat is around 76.
Cat Calorie Calculator - Estimates daily calorie needs for a cat from its body weight and life stage using the Resting Energy Requirement formula (RER = 70 x weight in kg to the power 0.75) and a maintenance factor. Covers neutered and intact adults, kittens, seniors, and weight-loss or weight-gain goals.
Horse Weight Calculator - Estimates a horse’s body weight from heart girth and body length using the standard weight-tape formula taught by veterinary extension services.
Cost of Owning a Dog Calculator - Estimates the annual and lifetime cost of owning a dog from food, vet, grooming, and other recurring expenses.
Dog BMI Calculator - Compares your dog’s current weight to its ideal weight as a percentage index, classifying the result as underweight, ideal, overweight, or obese, based on common veterinary weight guidance.
Cat BMI Calculator - Compares your cat’s current weight to its ideal weight as a percentage index, classifying the result as underweight, ideal, overweight, or obese, based on common veterinary weight guidance.
Why Pet Age Is Not Simply Seven Times Human Years
The old “multiply by seven” rule is a myth. Dogs and cats mature very quickly in their first two years, reaching the equivalent of a young adult by age two, then age more slowly and steadily after that. Size matters too: a giant-breed dog is considered senior years earlier than a small terrier. These calculators use the modern size-based and life-stage models that reflect how pets actually age, giving you a far more realistic picture than a single multiplier.
Frequently Asked Questions
How do you calculate a dog's age in human years?
Count the first year as about 15 human years, the second year as 9 more (24 total), then add 4 to 7 human years for each additional year depending on size. The Dog Age Calculator does this automatically for small, medium, large, and giant breeds.
How old is a cat in human years?
A 1-year-old cat is about 15 in human years, a 2-year-old about 24, and each year after that adds roughly 4. So a 5-year-old cat is about 36. Use the Cat Age Calculator for any age.
How many calories does my cat need per day?
Start with the Resting Energy Requirement, 70 times body weight in kilograms to the power 0.75, then multiply by a factor for life stage and goal. A typical neutered adult cat needs about 200 to 280 calories a day. The Cat Calorie Calculator works it out for you.
Do larger dogs age faster than small dogs?
Yes. After the first two years, giant and large breeds add more human-equivalent years per calendar year than small breeds, so they reach senior status earlier. The Dog Age Calculator accounts for this with a size selector.