Free online tool
BMI Calculator
Calculate your Body Mass Index using US or metric units.
Your BMI
How this is calculated
BMI = weight ÷ height2. We use the standard formula recommended by the CDC: 703 × weight (lb) ÷ height (in)² for US units, or kg ÷ m2 for metric.
Is BMI accurate for everyone?
BMI is a general screening measure. It doesn’t distinguish muscle from fat, so it can overestimate body fat in athletes and underestimate it in older adults with low muscle mass. It’s a starting point, not a diagnosis.
What are the BMI categories?
Underweight: below 18.5 · Normal weight: 18.5–24.9 · Overweight: 25–29.9 · Obesity: 30 and above.
Should I talk to a doctor about my result?
If your BMI is outside the normal range, or you have concerns about your weight or health, a healthcare provider can give you a full assessment that BMI alone can’t.
Free BMI Calculator: Check Your Body Mass Index
This BMI calculator helps you quickly find your Body Mass Index using either US units (pounds, feet and inches) or metric units (kilograms, centimeters). BMI is one of the most common ways to get a quick, general read on whether your weight falls within a typical range for your height.
Doctors, trainers, and insurers often reference BMI as a starting point — not a full picture — of overall health. This calculator uses the same formula recommended by the CDC, so results match what you’d get from a clinical BMI chart. Enter your weight and height above to calculate your BMI in seconds and see which category (underweight, normal weight, overweight, or obesity) it falls into.
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