Cat Food Calculator
Estimate daily calories and grams of wet or dry food for your cat.
Estimated daily energy need
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Treats should be no more than ~10% of daily calories — reduce meals accordingly. This is an estimate: individual needs vary by up to ±50%. Weigh your cat monthly and adjust by about 10% as needed, with your vet's advice.
How this calculator works
Veterinarians estimate a cat's energy needs using the Resting Energy Requirement (RER): 70 × (body weight in kg)^0.75. The RER is multiplied by a factor for life stage and activity — for example about 1.2 for a neutered adult, 2–3 for growing kittens, and around 0.8 of ideal-weight RER for supervised weight loss. The calculator then divides the daily calories by the calorie content of your food to give grams per day.
Find the calorie content of your food
Look on the pack or the manufacturer's website for "metabolizable energy", usually given as kcal/kg (dry food) or kcal per can or pouch (wet food). To convert a can: divide kcal per can by the can weight in grams and multiply by 100 to get kcal per 100 g.
Check and adjust
Every cat is different — needs can vary by up to 50% between cats of the same weight. Use the result as a starting point:
- Weigh the food on a kitchen scale.
- Weigh your cat every 2–4 weeks.
- Check body condition: you should be able to feel the ribs easily, and see a waist from above.
- Adjust by about 10% if your cat is gaining or losing weight unintentionally.
Read more in how much to feed a cat and overweight cats.