Pet Food Portion & Daily Calorie Calculator
Enter your pet's weight, age, and activity level to get their daily calorie needs (RER × MER) and the grams of their specific food to feed per day. Nothing uploaded.
Pet Details
Daily Feeding
These are estimates based on average metabolic rates. Monitor body condition and adjust amounts if the pet gains or loses weight. Consult a vet for medical conditions.
Learn more: how pet calorie needs are calculated
The formula
The tool follows the method in the AAHA 2021 nutrition and weight management guidelines. Resting energy requirement is RER = 70 x body weight in kg to the power 0.75, and maintenance energy requirement is MER = RER x a life stage factor. The AAHA's worksheet works an example for a 10 lb (4.5 kg) neutered dog: RER is 216 kcal a day, and with a factor of 1.4, MER is 302.
Because of the 0.75 exponent, doubling the weight does not double the food. A 10 kg dog has an RER of 70 x 10^0.75 = 394 kcal, or 39 kcal per kg. A 20 kg dog has 662 kcal, or 33 kcal per kg. A straight ratio of weight would give 788 kcal for the 20 kg dog.
Life stage factors
The AAHA worksheet lists these ranges for dogs: neutered adults 1.4 to 1.6, intact adults 1.6 to 1.8, weight loss 1.0, and growth 3.0 for puppies under 4 months and 2.0 from 4 months. For cats it lists neutered adults at 1.2 to 1.4, intact adults at 1.4 to 1.6, weight loss at 0.8 and growth at 2.5. It gives work ranges of 1.6 to 2.0 for light, 2.0 to 5.0 for moderate and 5.0 to 11.0 for heavy work.
The tool uses a single value from those ranges. For a neutered dog it uses 1.6, the top of the range, so a 10 kg neutered dog comes out at 630 kcal, against 551 at 1.4. For a neutered cat it uses 1.2, the bottom of the range. The senior options (1.4 for dogs, 1.1 for cats) are not in the worksheet. At 340 kcal per 100 g of food, 630 kcal is about 185 g a day.
The worksheet notes that these factors are general guidelines, that sedentary or indoor pets may need less, and that intake should be adjusted by monitoring body weight and body condition score.
FAQ
Why not feed by a simple ratio of body weight?
Energy needs scale with weight to the power 0.75, not 1. A weight ratio gives a 20 kg dog 788 kcal where the formula gives an RER of 662, and it favors neither small nor large pets consistently. Use the formula, then adjust by watching weight.
What is the difference between RER and MER?
RER is the baseline energy for an animal at rest. MER multiplies it by a life stage factor to estimate a day's needs. The tool shows both.
Should I use this instead of asking a vet?
No. It gives a starting estimate. Body condition, health problems and the food's calorie content all matter, so ask a veterinarian before you make a big change to a pet's diet. This is general information, not veterinary advice.