Canine / Feline BMI Calculator
Calculate a simple weight-to-length index for dogs or cats as a starting point for body condition assessment.
Results
What is it?
The Pet BMI Calculator computes a simple weight-to-length squared index for dogs and cats (analogous to human BMI). Rough reference ranges: dogs 12-22, cats 15-25. However, this is a very rough approximation — veterinary Body Condition Scoring (BCS) is far more accurate.
How to use
Enter your pet's weight in kg and body length in cm (chest to base of tail). The index is calculated as weight (kg) / length (m)^2. Compare to the rough reference ranges, but always prioritize BCS assessment.
Example scenario
A dog weighing 10 kg with a body length of 60 cm: 10 / (0.60)^2 = 10 / 0.36 = 27.8. This would suggest the dog may be overweight for its length, warranting a BCS evaluation.
Pro tip
BMI is not a validated veterinary tool for pets. The gold standard is the Body Condition Score (BCS) 1-9 scale: at BCS 5 (ideal), you should feel but not easily see the ribs, and the waist should be visible from above and the side. Ask your vet to teach you how to assess BCS — it takes 30 seconds and is far more informative than any weight-based index.