๐พ Pet Food Calculator
This is only a general guideline. Always consult a veterinarian to determine actual feeding amounts.
Enter your pet's weight, activity level, and the food's calorie density (kcal per 100g) to calculate its daily food amount, based on the Resting Energy Requirement (RER) and Daily Energy Requirement (DER) formulas widely used in veterinary nutrition.
How to use
- Enter your pet's weight (kg).
- Choose its activity level (neutered/intact adult, active, puppy/kitten growth, etc.).
- Enter the food's calorie density (kcal/100g, from the package) and how many meals per day โ the daily and per-meal amounts are calculated automatically.
How the calculation works
This tool calculates daily calorie needs and food amounts with the RER/DER formulas widely used in veterinary nutrition. RER (resting energy requirement) = 70 ร weight (kg)^0.75 DER (daily energy requirement) = RER ร factor Food per day (g) = DER รท (food energy (kcal/100 g) รท 100) Per meal = food per day รท meals per day Weight is raised to the power 0.75 because energy needs scale with metabolic body size rather than with weight directly. The factors used are, for dogs: neutered adult 1.6, intact adult 1.8, weight loss 1.0, active 2.0, growing 2.5; for cats: neutered adult 1.2, intact adult 1.4, weight loss 0.8, growing 2.5.
Worked example
Neutered dog, 5 kg, food at 350 kcal/100 g, 2 meals a day RER: 70 ร 5^0.75 โ 234 kcal DER: 234 ร 1.6 โ 374 kcal Food per day: 374 รท 3.5 โ 107 g Per meal: about 53 g Neutered cat, 4 kg, same food RER: about 198 kcal; DER: 198 ร 1.2 โ 238 kcal Food per day: about 68 g (using the dog factor of 1.6 would give about 91 g โ too much)
Things to be aware of
- Keep treats under 10% of daily calories and reduce the main food to match.
- Puppies need a factor of about 3.0 up to four months old and about 2.0 after that, so needs change a lot with age.
- Check weight and body condition every 2โ4 weeks and adjust the amount if your pet is gaining or losing too much.
- For pets under treatment, pregnant or nursing, always work out the amount with your vet.
FAQ
What are RER and DER?
RER (resting energy requirement) is the baseline calorie need calculated from body weight (70 ร weight in kg to the power 0.75). DER (daily energy requirement) is RER multiplied by a factor for the species and life stage, giving the calories actually needed per day. Cats have lower factors than dogs: a neutered adult is 1.6 for dogs but 1.2 for cats.
Where do I find the calorie density (kcal/100g)?
Most pet food packaging lists this as "metabolizable energy" (ME). If it's not listed, check the manufacturer's website or contact their customer support.
Is this calculation exact enough to just follow directly?
It's only a general estimate โ appropriate feeding amounts vary by individual factors like body condition, health status, and whether the pet is spayed/neutered. Always consult a veterinarian to set feeding amounts, especially for puppies/kittens, pregnant animals, or pets with health conditions.