Is BMI accurate for athletes?

BMI does not distinguish muscle from fat. Very muscular people may register as "overweight" or "obese" despite low body fat. For athletes, body fat percentage or waist measurements are often more useful.

Does BMI apply to children and teens?

For children and teens (under 20), BMI is plotted on age- and sex-specific growth charts and reported as a percentile, not a category. This calculator is designed for adults age 20 and over.

BMI Calculator

Calculate your Body Mass Index and see which weight category you fall into.

Inputs

Units

Imperial (lb, in)Metric (kg, cm)

Height*(in)

Your height in inches (imperial) or centimeters (metric).

Weight*(lb)

Your weight in pounds (imperial) or kilograms (metric).

Enter your values to see results instantly.

How this works

Formula

BMI = 703 × weight(lb) / height(in)² or weight(kg) / height(m)²

Body Mass Index (BMI) is a screening tool that uses your height and weight to estimate body fatness. It is widely used because it is quick, free, and requires only a scale and tape measure.

BMI categories are: under 18.5 = underweight, 18.5–24.9 = healthy, 25–29.9 = overweight, 30+ = obese. These ranges come from large population studies linking BMI to health risks.

BMI has limitations: it does not distinguish muscle from fat, so very muscular people can read as "overweight" despite being fit. It is a starting point, not a complete health picture — talk to your doctor for a full assessment.

Worked example

5'10", 180 lb (imperial)

UnitsImperial

Height70 in

Weight180 lb

Result

BMI = 703 × 180 / 70² = 25.8. This falls in the "overweight" category.

Frequently asked questions

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