{
  "id": "cat-calorie",
  "version": "d0690babab5c",
  "status": "published",
  "name": "Cat Calorie Calculator",
  "question": "How many cat calories per day?",
  "summary": "Estimates a cat’s daily calories from its weight and life stage: the resting energy requirement 70 × kg^0.75 times the Merck Veterinary Manual factor.",
  "category": "biology",
  "subcategory": "animals",
  "url": "https://www.acalculator.org/biology/cat-calorie-calculator",
  "markdown": "https://www.acalculator.org/biology/cat-calorie-calculator.md",
  "kind": "function",
  "method": "RER = 70 × (body weight in kg)^0.75 kcal a day; calories per day = RER × the life-stage factor (neutered adult 1.2, intact adult 1.4, inactive or obesity prone 1.0, kitten 2.5); cups or cans = calories ÷ the food’s calories per cup or can.",
  "assumptions": [
    "The factors are the Merck Veterinary Manual’s for healthy cats. Each cat differs, so the result is a starting point: weigh your cat every few weeks and adjust.",
    "For weight loss, ask your vet for a target weight and plan; this page does not give a weight-loss factor.",
    "Pregnant, nursing and sick cats need a vet’s plan. This page is for information only and is not veterinary advice."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "w": {
        "title": "Cat’s weight",
        "description": "Your cat’s body weight now (use the ideal weight your vet gives for a weight-loss plan).",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "minimum": 0.1,
        "maximum": 20
      },
      "stage": {
        "title": "Life stage",
        "description": "The life stage or activity, which sets the factor on the resting energy.",
        "type": "string",
        "enum": [
          "neutered",
          "intact",
          "prone",
          "kitten"
        ]
      },
      "food": {
        "title": "Food calories per cup or can",
        "description": "From the food label, in kcal per cup or per can. Leave empty to skip.",
        "type": "number",
        "minimum": 1,
        "maximum": 2000
      }
    }
  },
  "outputs": {
    "daily": {
      "label": "Calories per day",
      "description": "RER × the life-stage factor.",
      "format": "number"
    },
    "rer": {
      "label": "Resting energy (RER)",
      "description": "70 × body weight in kg raised to the power 0.75.",
      "format": "number"
    },
    "factor": {
      "label": "Life-stage factor",
      "description": "The Merck Veterinary Manual multiplier for this life stage.",
      "format": "number"
    },
    "portions": {
      "label": "Cups or cans per day",
      "description": "Calories per day ÷ the food’s calories per cup or can.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "w": 4.535923700000001,
      "stage": "neutered"
    },
    "outputs": {
      "daily": 261.0829982726086,
      "rer": 217.56916522717384,
      "factor": 1.2
    },
    "text": "A 10 lb cat needs about 261 calories a day at 1.2 × RER."
  },
  "examples": [
    {
      "given": {
        "w": 5,
        "stage": "neutered"
      },
      "expect": {
        "rer": 234.0591067417477,
        "daily": 280.87092809009727
      },
      "source": "Merck Veterinary Manual, Nutritional Requirements of Small Animals (S. L. Sanderson, reviewed Nov 2023): RER = 70 × BW(kg)^0.75; neutered 1.2, intact 1.4, obesity prone 1 × RER; kittens 2.5 × RER, https://www.merckvetmanual.com/management-and-nutrition/nutrition-small-animals/nutritional-requirements-of-small-animals; Python 3: 70 * 5 ** 0.75 * 1.2"
    },
    {
      "given": {
        "w": 4.535923700000001,
        "stage": "intact",
        "food": 400
      },
      "expect": {
        "rer": 217.56916522717384,
        "daily": 304.59683131804337,
        "portions": 0.7614920782951085
      },
      "source": "hand calculation in content.mdx: 10 lb = 4.5359237 kg; 70 × 4.5359237^0.75 × 1.4; Merck Veterinary Manual, Nutritional Requirements of Small Animals (S. L. Sanderson, reviewed Nov 2023): RER = 70 × BW(kg)^0.75; neutered 1.2, intact 1.4, obesity prone 1 × RER; kittens 2.5 × RER, https://www.merckvetmanual.com/management-and-nutrition/nutrition-small-animals/nutritional-requirements-of-small-animals"
    },
    {
      "given": {
        "w": 1.5,
        "stage": "kitten"
      },
      "expect": {
        "rer": 94.8782103790337,
        "daily": 237.19552594758426,
        "factor": 2.5
      },
      "source": "hand calculation in content.mdx: 70 × 1.5^0.75 × 2.5; Merck Veterinary Manual, Nutritional Requirements of Small Animals (S. L. Sanderson, reviewed Nov 2023): RER = 70 × BW(kg)^0.75; neutered 1.2, intact 1.4, obesity prone 1 × RER; kittens 2.5 × RER, https://www.merckvetmanual.com/management-and-nutrition/nutrition-small-animals/nutritional-requirements-of-small-animals"
    },
    {
      "given": {
        "w": 1,
        "stage": "prone"
      },
      "expect": {
        "rer": 70,
        "daily": 70
      },
      "source": "hand calculation in content.mdx: 70 × 1^0.75 × 1 = 70; Merck Veterinary Manual, Nutritional Requirements of Small Animals (S. L. Sanderson, reviewed Nov 2023): RER = 70 × BW(kg)^0.75; neutered 1.2, intact 1.4, obesity prone 1 × RER; kittens 2.5 × RER, https://www.merckvetmanual.com/management-and-nutrition/nutrition-small-animals/nutritional-requirements-of-small-animals"
    }
  ],
  "sources": [
    "Merck Veterinary Manual, Nutritional Requirements of Small Animals, by Sherry Lynn Sanderson (full review Nov 2023): RER = 70 × BW(kg)^0.75; daily maintenance energy for cats: intact 1.4, neutered 1.2, obesity prone 1 × RER; kittens 2.5 × RER. https://www.merckvetmanual.com/management-and-nutrition/nutrition-small-animals/nutritional-requirements-of-small-animals (retrieved 2026-10-02)",
    "National Research Council, Nutrient Requirements of Dogs and Cats (2006), Chapter 3, Energy (the energy requirements these factors build on). https://nap.nationalacademies.org/catalog/10668/nutrient-requirements-of-dogs-and-cats (retrieved 2026-10-02)",
    "NIST Special Publication 811, Appendix B (1 lb = 0.45359237 kg exactly). https://www.nist.gov/pml/special-publication-811 (retrieved 2026-10-02)"
  ],
  "related": [
    "dog-weight",
    "puppy-weight",
    "cat-age"
  ],
  "changelog": []
}