Pet Food Calculator
Calculate the exact daily calories and food portions your dog or cat needs based on weight, age, and activity level.
How Pet Food Calculator Works
Calculate exact daily food portions and calories for your dog or cat. and based on veterinary RER formulas. Enter your values into the form above and the calculator processes them instantly in your browser — no data is sent to any server.
How to Calculate Pet Food Portions
Overfeeding is the number one cause of pet obesity, which affects over 50% of dogs and cats in developed countries. This calculator uses the Resting Energy Requirement (RER) formula used by veterinarians to determine exactly how many calories your pet needs each day.
The RER Formula
Resting Energy Requirement (RER) = 70 x (body weight in kg) ^ 0.75. This gives the baseline calories a pet needs at rest. We then multiply by an activity factor based on your pet's lifestyle, age, and reproductive status to get their Daily Energy Requirement (DER).
Activity Factors
- Neutered adult (low activity): RER x 1.2–1.4
- Intact adult (moderate): RER x 1.6–1.8
- Active/working dog: RER x 2.0–5.0
- Puppy/kitten: RER x 2.0–3.0
- Weight loss: RER x 1.0
Feeding Schedule
Puppies under 6 months should eat 3–4 times per day. Puppies 6–12 months can eat 2–3 times daily. Adult dogs do well with 2 meals per day. Cats often prefer 2–3 smaller meals or even free-feeding with measured daily portions.
Reading Pet Food Labels
Check the "kcal/cup" or "kcal/can" on your pet food label. Premium foods typically have 350–500 kcal per cup for dry food. Wet food has fewer calories per volume. Once you know the calories per cup, divide your pet's daily calorie needs by that number to get the cups per day.
Signs of Overfeeding
If you cannot feel your pet's ribs with light pressure, they may be overweight. Other signs include difficulty breathing during exercise, reluctance to move, and visible fat deposits. Obesity shortens a pet's lifespan by an average of 2.5 years and increases the risk of diabetes, joint disease, and cancer.
Frequently Asked Questions
How many calories does my dog need per day?
It depends on weight, age, and activity level. A 25 lb moderately active adult dog needs roughly 550–700 calories per day. Use the RER formula: 70 x (weight in kg)^0.75, then multiply by the appropriate activity factor.
How many times a day should I feed my pet?
Puppies under 6 months need 3–4 meals daily. Adult dogs do well with 2 meals. Cats prefer 2–3 smaller meals. Senior pets may benefit from smaller, more frequent meals.
How do I know if I am overfeeding my pet?
If you cannot easily feel your pet's ribs with light pressure, they may be overfed. Look for a visible waist when viewed from above and a tucked abdomen from the side.
Should I feed wet or dry food?
Both can provide complete nutrition. Dry food is more calorie-dense and better for dental health. Wet food provides extra hydration and is often more palatable. Many owners mix both.
Does spaying or neutering affect food needs?
Yes. Spayed and neutered pets have lower metabolic rates and need about 20–30% fewer calories than intact pets. Without adjusting portions, fixed pets often gain weight.
How do I calculate cups of food per day?
Check your food label for kcal per cup. Divide your pet's daily calorie needs by that number. For example, if your dog needs 600 kcal and the food has 400 kcal/cup, feed 1.5 cups per day.