How the bMI Calculator works
BMI relates weight to height squared and is the screening number used across healthcare and research. The standard adult ranges are under 18.5 underweight, 18.5 to 24.9 normal, 25 to 29.9 overweight, and 30 plus obese.
BMI = 703 × weight(lb) ÷ height(in)²
Example: 5 foot 10 and 170 lb is a BMI of 24.4, inside the normal range, which for that height spans about 129 to 174 lb.
Frequently asked questions
Is BMI accurate for everyone?
It is a population screening tool, not a diagnosis. Muscular people can read high without excess fat, and older adults can read normal while carrying little muscle. Waist measurement and body fat percentage add the missing context.
Does BMI differ for men and women?
The adult formula and categories are identical for both. Children and teens instead use age and sex specific percentile charts.
What should I do about my BMI number?
Treat it as one data point. A clinician looking at the whole picture, including blood work and waist size, is the right interpreter of what any single number means for you.