Daily calorie needs vary significantly by breed, weight, age, and activity level. Our breed calculator uses the NRC 2006 Resting Energy Requirement formula (RER = 70 × body weight in kg^0.75) with breed-specific multipliers. For example, a 30 lb adult Labrador Retriever needs roughly 1,000–1,200 kcal/day at moderate activity, while a 30 lb English Bulldog needs only 750–900 kcal due to lower metabolic rate. Small breed dogs like Chihuahuas have higher per-pound calorie needs than giant breeds like Great Danes.

Cat calorie needs depend on breed, weight, age, and whether they are indoor or outdoor cats. A typical 10 lb indoor adult cat needs about 200–250 kcal/day, while an active outdoor cat of the same weight may need 300+ kcal/day. Our cat calorie calculator accounts for breed-specific metabolism — active breeds like Bengals and Siamese need more calories than sedentary breeds like Persians. Indoor cats typically need 15–20% fewer calories than outdoor cats.

Results are based on the NRC 2006 Resting Energy Requirement formula and WSAVA guidelines, with breed-specific metabolic factors reviewed by our Veterinary Advisory Board. They provide a clinically-aligned starting point, but individual variation (metabolism, environment, health conditions) means you should consult your vet for a final feeding plan. See our Methodology page for full details on the calculation.

Yes. The calculator offers adjustments for neuter status, overweight/underweight condition, diabetes, and kidney disease. Each adjustment applies a clinically-aligned multiplier to the base energy requirement. However, pets with medical conditions should always be managed under direct veterinary supervision — our estimates are a starting point, not a prescription.

The old "multiply by 7" rule is scientifically inaccurate. Our breed age calculator uses breed-specific aging curves based on veterinary research. Small breeds (under 20 lbs) age much slower than giant breeds (over 100 lbs). A 5-year-old Chihuahua is roughly 36 in human years, while a 5-year-old Great Dane is about 45. Mixed breed dogs are calculated based on their weight category. This dog age calculator also accounts for the accelerated aging in the first 2 years of life.

Cats age rapidly in their first two years: year 1 equals roughly 15 human years, and year 2 adds about 9 more. After that, each cat year adds approximately 4 human years. A 5-year-old cat is about 36 in human years. Our calculator handles this automatically for 73+ cat breeds with breed-specific data.

Research suggests larger dogs age faster at the cellular level. Giant breeds like Great Danes have average lifespans of 7–10 years, while small breeds like Chihuahuas may live 14–18 years. The exact mechanisms are still being studied, but accelerated growth rates and higher oxidative stress in large breeds are leading theories. This size-lifespan relationship is factored into our breed-specific aging curves.

Our breed weight calculator (also called a breed size calculator) predicts a puppy's adult weight based on their breed, current age, and current weight. It uses breed-specific growth curves to estimate final adult size. Small breeds reach adult weight by 10–12 months, medium breeds by 12–16 months, and giant breeds may continue growing until 18–24 months. The calculator covers 350+ dog breeds with accurate growth data.

Accuracy improves as your puppy gets older, because a larger proportion of their growth is already measured. At 4 months, predictions for a known breed are typically within 10–15% of the actual adult weight. By 6–8 months, accuracy improves to within 5–10%. Purebred dogs with well-established growth curves tend to have the most accurate predictions. Mixed breeds show wider natural variation.

Dog pregnancy (gestation) typically lasts 58–68 days, with an average of 63 days from ovulation. Our breeding calculator helps track important milestones including heat cycles, optimal breeding dates, expected whelping date, and puppy development stages week by week. Cat pregnancy is shorter at 58–67 days (average 65 days).

Enter your dog's breed and the mating date, and the calculator provides a complete week-by-week gestation timeline with key milestones: embryo implantation (day 19–21), heartbeat detection by ultrasound (day 25), sex determination (day 35), and expected whelping date (day 63). Most female dogs come into heat twice a year, with the fertile period typically 9–14 days after the start of estrus.

Yes! All four breed calculators (calorie, age, weight, and breeding) are 100% free to use with no sign-up required. We cover 350+ dog breeds and 73 cat breeds. You can run unlimited calculations — all completely free.

BreedCalc supports every AKC, FCI, and UKC recognized dog breed — over 350 breeds total. This includes popular breeds like Labrador Retriever, German Shepherd, Golden Retriever, French Bulldog, Poodle, Beagle, Rottweiler, Dachshund, and Yorkshire Terrier, as well as rare breeds and designer crossbreeds (Goldendoodle, Labradoodle, Cockapoo, Bernedoodle, etc.). We also support mixed breed dogs in four size categories.

We cover 73 cat breeds recognized by TICA (The International Cat Association) and CFA (Cat Fanciers' Association). This includes Domestic Shorthair, Maine Coon, Siamese, Persian, Ragdoll, Bengal, British Shorthair, Abyssinian, Scottish Fold, Sphynx, and many more. Each cat breed has specific metabolism data, indoor/outdoor activity adjustments, and breed-typical weight ranges.

Yes. Mixed-breed dogs are calculated based on their weight category (small, medium, large, giant) using generalized factors. If you know one or both parent breeds, you can select the closest match for more specific results. The calorie and age calculators both support a "Mixed Breed" option with size-based calculations.

Our primary sources are the NRC Nutrient Requirements of Dogs and Cats (2006), WSAVA Global Nutrition Guidelines, AAHA Canine Life Stage Guidelines (2019), AAFCO nutrient profiles, FEDIAF nutritional guidelines, and peer-reviewed aging research. See our full Scientific References page for complete citations.

We currently offer dedicated age calculators for Holland Lop Rabbits, Guinea Pigs, Cockatiels, and Ferrets. Calorie calculations focus on dogs and cats. We plan to expand exotic-pet coverage over time — check our Blog for updates.