Cat BMI Calculator

Is your feline friend fit or flabby? Use this scientific FBMI tool to assess your cat's body condition based on physical measurements rather than just weight.

Feline BMI (FBMI) Calculation: 1. Ribcage Factor: (Ribcage circumference / 0.7062) 2. Height Offset: (Factor - Lower Leg length) 3. Scaling: (Offset / 0.9156) 4. Final Calculation: (Result - Lower Leg length) Note: This formula estimates body fat percentage based on skeletal and soft tissue measurements.
Scenario: A domestic shorthair cat has a rib cage circumference of 35 cm and a lower back leg length of 15 cm. Calculation: 1. Ribcage / 0.7062 ≈ 49.56. 2. 49.56 - 15 = 34.56. 3. 34.56 / 0.9156 ≈ 37.75. 4. 37.75 - 15 = 22.75. Result: The FBMI is 22.8, which falls within the "Healthy" range (15 - 30).

How is Cat BMI (FBMI) calculated?

The Feline Body Mass Index (FBMI) is calculated using the circumference of the rib cage and the length of the lower back leg (limbs). The formula is: FBMI = (((Rib cage / 0.7062) - leg length) / 0.9156) - leg length.

What is a healthy FBMI for a cat?

A healthy FBMI for a typical adult cat ranges from 15 to 30. An FBMI over 30 generally indicates that the cat is overweight or obese.

Why is Cat BMI different from Human BMI?

Human BMI only uses height and weight. Since cats vary significantly in body shape and fur thickness, FBMI uses skeletal measurements (leg length) and chest circumference to provide a more accurate estimate of body fat percentage.

How do I measure my cat correctly?

Use a soft measuring tape. Measure the rib cage circumference at the level of the 9th rib (usually the widest part of the chest). Measure the leg length from the knee (patella) to the heel (calcaneus).

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