Free Pet Health & Diet Calculator

Estimate daily calories and food portions for a healthy dog or cat. Free, private and instant—no sign-up required.

⚙️ Smart Engine Rule-based • Private • Instant
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Choose your pet

Select the calculator that matches your pet.

Basic details

Body & lifestyle

Weight-management results are general starting guidance, not a medical weight-loss prescription.

Food details

YOUR PERSONALIZED PLAN

Intelligent Feeding Recommendation for Your pet

Resting Energy (RER)—kcal/day
Estimated Daily Energy—kcal/day
Food per day—grams
Food per meal—grams
Treat allowance—kcal maximum (10%)
Multiplier used—life-stage factor
SMART INSIGHTS

Why this plan fits your inputs

WELLNESS SNAPSHOT

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Based on 7 data points: species, age, weight, activity, body condition, food type and meals per day.

Important: This calculator provides general feeding estimates for healthy dogs and cats and is intended for educational purposes only. Individual calorie needs vary. Puppies, kittens, pregnant or nursing pets, animals with medical conditions, pets on therapeutic diets, or pets requiring significant weight change should be assessed by a qualified veterinarian.

How we calculate

We first estimate your pet’s Resting Energy Requirement (RER) using:

RER = 70 × body weight (kg)^0.75

We then apply a dog- or cat-specific life-stage multiplier to estimate daily energy needs. Food quantity is calculated using the calorie information provided on your pet-food label.

These results are starting estimates, since individual calorie requirements can vary considerably between pets.

Sources: Merck Veterinary Manual and WSAVA Global Nutrition Guidelines. ZyZig is not endorsed by, affiliated with, or officially associated with these organisations.

Why calorie requirements vary

Two pets of the same weight may need different amounts of food depending on factors such as:

  • Age and life stage

  • Neuter status

  • Activity level

  • Body condition and weight goals

  • Breed and body size

  • Environment

  • Overall health

When to contact a vet

Speak with a qualified veterinarian if your pet is a puppy or kitten with unusual growth, is pregnant or nursing, has experienced significant weight change, has an illness or requires a therapeutic diet, or has persistent changes in appetite, vomiting, diarrhoea, or other health concerns.

Frequently asked questions

Is this calculator free?

Yes. It is free, requires no account and shows results instantly.

Are the results veterinary advice?

No. They are general educational estimates for healthy dogs and cats.

Where do I find food calories?

Check the packaging or manufacturer website for kcal per 100g, cup, can or pouch.

Why might my pet need a different amount?

Breed, age, neuter status, activity, body condition, environment and health can all affect energy needs.