Pet Food Calculator — How Much to Feed Your Dog & Cat

It depends on your dog's weight, life stage, and activity — the classic "how much to feed my dog calculator" question. Veterinarians use the RER formula (70 × weight in kg^0.75) multiplied by a life-stage factor — for example a 20 kg neutered adult dog needs about 1,059 kcal per day, which is roughly 303 grams (3 cups) of a typical 350 kcal/100g kibble, split over 2 meals. Use the calculator above with your dog's exact details for a precise figure.

RER stands for Resting Energy Requirement — the calories an animal needs at rest in a thermoneutral environment. The standard veterinary formula is RER = 70 × (body weight in kg)^0.75. For example, a 20 kg dog has an RER of about 662 kcal/day. RER is the starting point; daily needs (MER) are RER multiplied by factors for life stage and activity.

MER (Maintenance Energy Requirement), also called DER (Daily Energy Requirement), equals RER multiplied by a life-stage factor. Standard veterinary multipliers for dogs: neutered adult 1.6, intact adult 1.8, puppy 0–4 months 3.0, puppy 4–12 months 2.0, senior 1.2–1.4, weight loss 1.0, working dog 2–8. For cats: neutered adult 1.2, intact adult 1.4, kitten 0–4 months 2.5, kitten 4–12 months 2.0, weight loss 0.8.

A typical neutered adult dog needs RER × 1.6. Examples: a 10 kg dog needs about 630 kcal/day, a 20 kg dog about 1,059 kcal/day, and a 30 kg dog about 1,436 kcal/day. Puppies need far more (up to 3× RER), while seniors need less (about 1.2–1.4× RER). Enter your dog's weight and life stage in the calculator for an exact number.

A typical neutered adult cat needs RER × 1.2. For example, a 4.5 kg neutered cat needs about 260 kcal/day. Kittens need much more (2.0–2.5× RER), and overweight cats on a weight-loss plan are typically fed at 0.8× RER. Always transition diets gradually and consult your vet for medical conditions.

Divide the food's kcal per cup by its kcal per 100g, then multiply by 100. For example, a kibble with 350 kcal/cup and 350 kcal/100g means 1 cup weighs 100 grams. Kibble density varies widely (roughly 80–130 g per cup), so check your bag's label. The calculator above does this conversion automatically when you enter both values.

Puppies need 2–3× their RER depending on age: 3.0× for puppies under 4 months and 2.0× from 4 months to adulthood, split into 3–4 meals per day. For example, a 10 kg puppy under 4 months needs about 1,181 kcal/day. Large-breed puppies should be fed a large-breed puppy formula to control growth rate — ask your vet.

Senior dogs (7+ years, or 5+ for giant breeds) typically need 1.2–1.4× RER because metabolism slows. For example, a 30 kg senior dog with low activity needs about 1,131 kcal/day. Senior formulas with joint support and controlled phosphorus can help — your vet can advise based on bloodwork.

Veterinary weight-loss plans typically feed at 1.0× RER for dogs (0.8× RER for cats), which for a 20 kg dog is about 662 kcal/day — roughly 37% less than maintenance. Weigh your dog every 2 weeks and aim for 1–2% body weight loss per week. Never crash-diet a pet; work with your vet, especially for cats, where rapid weight loss can cause fatty liver disease.

It depends on the food's calorie density — the classic 'how much wet food to feed cat' question. Typical wet food has about 85 kcal per 100 g. A 4.5 kg neutered cat needing 260 kcal/day would need about 306 g of wet food daily (usually split into 2–3 meals). Check your can's label for exact kcal, since wet food ranges from 70–120 kcal/100 g.

Yes. Decide what share of daily calories comes from wet food (e.g. 50%), then convert each share separately: wet grams = (daily kcal × wet share) ÷ (wet kcal per 100 g) × 100, and dry grams = (daily kcal × dry share) ÷ (dry kcal per 100 g) × 100. The calculator's wet/dry split slider does this math for you automatically.

Yes. Neutered/spayed pets need fewer calories: the standard factor drops from 1.8 to 1.6 for adult dogs and from 1.4 to 1.2 for adult cats. This is one of the most common reasons pets gain weight after surgery — most owners keep feeding the same amount. Reduce portions by about 10–15% after neutering and monitor weight.

General guidance: puppies under 6 months 3–4 meals/day, adult dogs 2 meals/day, senior dogs 2 (sometimes 3 smaller) meals/day. Kittens under 6 months 3–4 meals/day, adult cats 2–3 meals/day. Divide the calculator's daily grams or cups by the number of meals. Consistent timing helps digestion.

No. This calculator provides general nutritional guidance based on standard published veterinary formulas (RER/MER). It is not a substitute for professional veterinary advice, diagnosis, or treatment. Pregnant, nursing, growing, ill, or severely overweight animals have special needs — always consult your veterinarian, especially before starting a weight-loss plan.

Formulas give a population-average starting point. Individual variation is large: metabolism, exact body condition score, unmeasured treats (which can add 10–30% of calories), and medical conditions all shift needs. Vets adjust based on hands-on body condition scoring and weigh-ins. Use the calculator's figure as a baseline, then adjust up or down based on your pet's weight trend over 2–4 weeks.

Kittens need 2.0–2.5× RER: 2.5× under 4 months and 2.0× from 4–12 months, split into 3–4 meals daily. For example, a 2 kg kitten under 4 months needs about 294 kcal/day. Feed a kitten-specific formula until about 12 months of age, then transition to adult food over 7–10 days.