Pet Calorie Calculator
Work out the daily calorie needs of a dog or cat from its weight and activity.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
This calorie estimate uses a resting-energy formula and a selected activity factor. Actual needs vary with age, body condition, neuter status, health and food energy density; confirm feeding targets with your veterinarian and the food label.
Worked example
calculated with the default values below
Pet Dog · Body weight 30 lb · Activity level Normal Daily calories 794 kcal/day · Weight 13.61 kg · Resting energy requirement 496 kcal/day · Calories per pound 26.5 kcal/lb · Feeding note Split the daily amount across at least two meals
General background references
Disclaimer
These calculators offer general guidance and do not replace veterinary advice. Individual animals vary with breed, weight, health status and medication. Suspected poisoning from chocolate, medication, plants or chemicals is an emergency — contact your veterinarian or a pet poison control service immediately rather than relying on a calculator.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
RER = 70 × W^0.75; D = RER × F; W = lb × 0.45359237
- D
- Daily calories (kcal)
- W
- Body weight (kg)
- F
- Activity factor
- RER
- Resting energy need
F = 1.2/1.6/2.2/1.0 (low/normal/active/weight loss); W floor 0.1 kg; cats are also multiplied by 0.8 and 1.25.
Frequently asked questions
Why does a small dog need more calories per pound than a large one?
Calorie need uses the 0.75 power of weight, not a straight line, so each added pound contributes less than the last. The resting energy requirement is 70 times weight-in-kg to the 0.75, then multiplied by the activity factor (1.6 for normal). A 5 lb Chihuahua and a 120 lb Great Dane therefore do not scale evenly: per-pound need is highest at low weight and the calculator's calories-per-pound output falls from roughly 40 toward 20 as the dog grows.