Cat BMI Calculator
Calculate your cat's Feline Body Mass Index (FBMI) to assess body condition and weight status
Calculate Cat BMI
đ Measurement Instructions
Rib Cage Circumference: Measure around your cat's chest at the 9th rib level (near the front legs)
Leg Length: Measure the lower back leg from knee to ankle while cat is standing upright
đĄ Ensure your cat is standing calmly with head upright for accurate measurements
Measure around chest at 9th rib level
Measure from knee to ankle on back leg
Cat BMI Results
Enter both measurements to calculate your cat's BMI
đ FBMI Formula Explanation
Feline Body Mass Index Formula:
FBMI = (Rib Cage Circumference)^0.70622 - (Leg Length)^0.9156
This formula estimates body fat content based on cat body proportions, developed specifically for feline body condition assessment.
FBMI Classification Ranges
| FBMI Range | Category | Description |
|---|---|---|
| < 15 | Underweight | Below normal weight range |
| 15 - 29.9 | Normal | Healthy weight range |
| 30 - 42 | Overweight | Above normal weight range |
| > 42 | Obese | Significantly overweight |
Example Calculation
Cat with 14 inch rib cage and 2 inch leg
Rib Cage Circumference: 14 inches (35.56 cm)
Leg Length: 2 inches (5.08 cm)
Rib Component: 35.56^0.70622 = 14.38
Leg Component: 5.08^0.9156 = 4.34
Final Calculation
FBMI = Rib Component - Leg Component
FBMI = 14.38 - 4.34
FBMI = 44.4 (Obese category)
Target rib cage for healthy weight: ~10 inches
Measurement Guide
Prepare Your Cat
Ensure cat is standing calmly
Head upright, all four paws on ground
Rib Cage Measurement
Wrap measuring tape around chest
At 9th rib, near front legs
Leg Measurement
Measure lower back leg
From knee joint to ankle
Weight Management Tips
Control portions and limit treats
Increase interactive playtime
Switch to high-protein, low-carb food
Monitor progress with regular measurements
Consult veterinarian for diet plans
Understanding Cat BMI and Body Condition
What is Feline BMI?
The Feline Body Mass Index (FBMI) is a specialized measurement system developed specifically for cats. Unlike human BMI which uses height and weight, FBMI uses body proportions - specifically rib cage circumference and leg length - to estimate body fat content and overall body condition.
Why These Measurements?
- âĸRib Cage: Reflects fat accumulation around vital organs
- âĸLeg Length: Represents structural body size independent of weight
- âĸProportional Assessment: More accurate than weight alone
- âĸBreed Independent: Works across different cat breeds
Health Implications
Obesity Risks
Diabetes, arthritis, heart disease, reduced lifespan
Underweight Risks
Malnutrition, weakened immune system, muscle loss
Healthy Weight Benefits
Increased energy, longer lifespan, better mobility
Important: FBMI is a screening tool. Always consult your veterinarian for comprehensive health assessment and personalized weight management plans.