Pet food portion calculator
This calculator gives a rough starting estimate of the daily calories and food a dog or cat needs. It is not feeding advice: follow your vet and the label of your food.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose dog or cat and enter the weight (for weight loss, enter the target weight).
- Pick the life stage and enter the energy content of the food in kcal per 100 g.
- Set the number of meals.
How it works
RER = 70 × kg^0.75. Daily calories = RER × life-stage multiplier. Food per day = calories ÷ kcal per 100 g × 100. This is a rough estimate; follow your vet and the food label.
Worked example
A neutered 10 kg dog: RER = 70 × 10^0.75 = 393.6 kcal. × 1.6 = 630 kcal a day. At 350 kcal per 100 g: 180 g of food, or 90 g in each of 2 meals.
Tips
- Weigh your pet regularly and adjust the portion by body condition, not just by the number.
- Switching foods changes the calories per gram: update the field.
- Ask your vet about a diet for pets with health conditions.
Frequently asked questions
Is this feeding advice?
No. It is a rough estimate from a standard formula. Individual animals differ a lot in activity and metabolism, so follow your vet and the feeding guide on your food, and adjust by watching body condition.
Where do the numbers come from?
Resting energy requirement is RER = 70 × (weight in kg)^0.75. The daily need is RER times a life-stage multiplier: neutered adult dog 1.6, intact 1.8, inactive 1.2, weight loss 1.0, puppy 2.0 to 3.0; adult cat 1.2 neutered, 1.4 intact, 1.0 inactive, 0.8 weight loss, kitten 2.5.
Where do I find the kcal on my food?
The packaging lists “metabolisable energy” in kcal per kg or per 100 g. Dry food is often 330–400 kcal per 100 g, wet food much less, so check yours.
Does it include treats?
No. Treats should be a small share of daily calories, so reduce the meal amount accordingly.