BMI Calculator

Calculate your Body Mass Index and see where you fall on the healthy weight spectrum.

lbs
ft
in
Your BMI
0
-
UnderweightNormalOverweightObese

How to Calculate BMI

Body Mass Index (BMI) is a simple measure of body fat based on height and weight. The formula differs slightly depending on whether you use metric or imperial units:

BMI = weight (kg) / height (m)2

BMI = (weight (lbs) x 703) / height (in)2

BMI provides a quick screening tool, not a diagnostic one. It does not distinguish between muscle and fat, so athletes with high muscle mass may have a high BMI without being overweight. It also does not account for bone density, age, sex, or ethnicity, all of which affect body composition.

BMI Categories

The World Health Organization defines BMI categories as follows: Underweight is below 18.5, Normal weight is 18.5 to 24.9, Overweight is 25 to 29.9, and Obese is 30 and above. These ranges are based on population-level health risks and may not apply equally to all individuals.

Limitations of BMI

BMI is a useful starting point but has well-documented limitations. It tends to overestimate body fat in muscular individuals and underestimate it in older adults who have lost muscle mass. Waist circumference, body fat percentage, and metabolic health markers often provide a more complete picture of health than BMI alone.

Note: This calculator is for informational purposes only. BMI is a screening tool and not a medical diagnosis. Consult your healthcare provider for personalized health advice.

BMI Calculator FAQ

What is a healthy BMI?
A BMI between 18.5 and 24.9 is generally considered healthy for most adults. However, BMI alone does not determine health status. Factors like muscle mass, overall fitness, and metabolic health also play important roles.
Does BMI apply to athletes?
BMI can be misleading for athletes and people with high muscle mass. Muscle is denser than fat, so a muscular person may have a high BMI while having a low body fat percentage. Body composition tests provide more accurate assessments for athletes.
Is BMI different for men and women?
The BMI formula and category ranges are the same for adult men and women. However, women typically have more body fat than men at the same BMI, which is why some health professionals consider additional metrics like waist-to-hip ratio.