Back to tools

Cat Calorie Calculator (RER/MER)

Calculate your cat's daily caloric needs based on weight and life stage.

Enter your cat's details:

Related Feline Calculators

Cat Age to Human Years Calculator
Pet Cost Calculator

The Two-Step Feline Calorie Calculation

To calculate the total daily calories (MER) for a cat, veterinary professionals first determine the **Resting Energy Requirement (RER)**.

    To calculate the total daily calories (MER) for a cat, veterinary professionals first determine the **Resting Energy Requirement (RER)**.

    • **RER Formula:** For cats, RER is usually calculated using the formula: **(30 x Weight_kg) + 70**. This calculates the calories needed just for the cat's organs to function at rest.
    • **MER (Daily Needs):** The RER is then multiplied by a **Metabolic Factor** (listed in the calculator) that accounts for whether the cat is an inactive adult (1.2), a rapidly growing kitten (3.0), or on a weight loss diet (0.8).

*Obesity is a major health concern for cats. If your cat is overweight, using the **Weight Loss** factor (0.8 x RER) is a vet-recommended starting point for safe and gradual calorie restriction.*