Pet Food Calculator

Veterinary Endocrinology & Clinical Nutrition Metrology

Veterinary nutritionists calculate daily feeding portions using metabolic body size equations:

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• Metabolic Calorie Formulas**:

Body Weight (kg) = Weight (lbs)2.20462

Resting Energy Requirement (RER) = 70 × (W_kg)^0.75

Daily Energy Requirement (DER) = RER × M_LifeStage

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• Life Stage Multipliers (M_LifeStage)**:

• Neutered Adult Dog: 1.6 × RER

• Intact Adult Dog: 1.8 × RER

• Weight Loss Dog: 1.0 × RER

• Active / Agility Dog: 2.0 × RER

• Neutered Adult Cat: 1.2 × RER

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• Portion Sizing & Bag Longevity Metrology**:

Daily Cups = DERFood Calorie Density

Bag Duration (Days) = Bag Weight (lbs) × 4 cups/lbDaily Cups

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• Standard Breed Benchmarks**:

• Indoor Cat (10 lbs): 216 kcal/day | 12 lb bag = 80 Days

• French Bulldog (25 lbs): 692 kcal/day | 15 lb bag = 33 Days

• Golden Retriever (50 lbs): 1,164 kcal/day | 30 lb bag = 38 Days

• German Shepherd (75 lbs Active): 1,939 kcal/day | 30 lb bag = 23 Days

How to Use This Calculator

Enter your Pet Body Weight (lbs) (e.g. 50 in lbs), Species, Neutered Status & Activity Level — choose from Dog: Neutered Adult (Standard 1.6 x RER), Dog: Intact Adult (1.8 x RER), Dog: Weight Loss / Sedentary Senior (1.0 x RER), Food Calorie Density (kcal per standard measuring cup) (e.g. 375 in kcal/cup), Dry Food Bag Size (Weight) (e.g. 30 in lbs), Price per Bag of Food (e.g. 65 in ), and Veterinary Breed Benchmark — choose from Custom Pet Profile, Golden Retriever (50 lbs, Neutered Adult) → 1,164 kcal/day (3.1 cups/day) | 30 lb bag lasts 38 Days (51/mo), Indoor Cat (10 lbs, Neutered) → 216 kcal/day (0.6 cups/day) | 12 lb bag lasts 80 Days (17/mo). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Body Weight in kg: W_kg = W_lbs / 2.20462

Resting Energy Requirement (RER) = 70 * (weightKg ^ 0.75)

Dry kibble standard: ~1 cup = ~100 to 110 grams (standard 105g/cup)

Worked Example

A pet owner with a 50 lb Golden Retriever discovers their dog needs 1,164 kcal/day (3.1 cups), preventing the common 1-cup overfeeding mistake that causes excess weight gain, and learns a 30 lb bag lasts 38 days.

Understanding Your Result

This calculation gives a precise result based on the inputs you provided. For practical decisions, consider whether the result changes meaningfully with slight variations in your inputs — if a 5–10% change in input causes a significant output change, gather more precise input data before deciding. Use this tool to quickly compare multiple scenarios side by side.