BMI Calculator
Body Mass Index (BMI) is a screening measure of body fat based on height and weight. Use imperial (feet, inches, pounds) or metric units to find your BMI category and healthy weight range.
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Frequently asked questions
What is a healthy BMI?
The CDC defines BMI 18.5–24.9 as the 'healthy' range for adults. Below 18.5 is underweight; 25.0–29.9 is overweight; 30.0+ is obese. These ranges apply to most adults age 20+.
Is BMI accurate?
BMI is a quick screening tool, not a diagnostic measure. It can misclassify athletes (high muscle mass = high BMI) and older adults (lower muscle, higher fat at the same BMI). Body fat percentage, waist-to-height ratio, and metabolic markers give a fuller picture.
Is BMI calculated differently for men and women?
No — the formula and category cutoffs are the same. However, women on average have a higher healthy body fat percentage than men at the same BMI, which is why BMI alone is a limited tool.
What's the BMI formula?
Metric: BMI = weight (kg) ÷ height (m)². Imperial: BMI = (weight in lbs ÷ height in inches²) × 703.