BMI Calculator

Calculate your Body Mass Index (BMI) with instant results. Understand what the number means and its limitations.

ft
in
lbs

Formula

BMI = 703 × weight(lb) / height(in)²

The 703 factor converts lbs/in² to kg/m².

23.63
Normal weight
BMI = 23.63
1018.5253040+

BMI Categories (WHO Standard)

Underweight
< 18.5
Normal weight
18.5 – 24.9You
Overweight
25 – 29.9
Obese Class I
30 – 34.9
Obese Class II
35 – 39.9
Obese Class III
≥ 40

Why BMI Has Limitations

BMI does not distinguish between muscle and fat mass. Athletes and very muscular individuals often register as "overweight" or "obese" despite having low body fat.

BMI also does not account for age, sex, ethnicity, or fat distribution. Abdominal fat (waist circumference) is often a stronger predictor of metabolic risk. Use BMI as a rough screening tool only.