Practical, evidence-aware guidance to help you understand pet calories and food labels.
How many calories does my dog need?
Understand RER and daily energy estimates for dogs.
How much should I feed my cat?
Estimate cat calories and convert them into food portions.
What is RER?
Learn how the recognised resting energy formula works.
How to read food calories
Find and use kcal per 100g, cup, can or pouch.
How we calculate
We first estimate Resting Energy Requirement (RER) using 70 × body weight in kilograms0.75. We then apply a dog- or cat-specific life-stage multiplier. Food quantity is calculated from the calorie information on your pet-food label. Results are starting estimates because individual needs vary.
Sources: Merck Veterinary Manual and WSAVA Global Nutrition Guidelines. ZyZig is not endorsed by these organisations.
When to contact a vet
Speak with a qualified veterinarian for puppies or kittens with unusual growth, pregnant or nursing pets, significant weight change, illness, therapeutic diets, persistent appetite changes, vomiting, diarrhoea or other health concerns.