Weight screening tool
Calculate body mass index from height and weight, then compare the result with the standard adult BMI categories.
Complete every visible field, then calculate.
Method
BMI = weight in kilograms / height in meters^2
Practical context
Body mass index compares weight with height and places the result in a standard adult screening category. It is quick and widely used, but it does not measure body fat, muscle mass, fitness, or health by itself.
BMI stands for body mass index. Metric BMI is weight in kilograms divided by height in meters squared. The imperial form multiplies weight in pounds by 703 and divides by height in inches squared.
Because it uses only height and weight, BMI is best treated as a population screening tool. It can identify a range worth discussing, but it cannot diagnose an individual condition.
The calculator applies the commonly used adult categories below. Category cutoffs do not represent sudden biological changes at one decimal point, so interpret values near a boundary with context.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Normal weight |
| 25.0 to 29.9 | Overweight |
| 30.0 and above | Obesity |
BMI can provide a consistent height-adjusted weight comparison and a useful starting point for broad risk screening. It cannot separate fat mass from muscle, bone, water, or other tissue.
A muscular athlete may receive a high BMI despite a lower body fat percentage. A person within the normal category may still have health risks that BMI cannot see. Age, sex, fat distribution, medical history, and ethnicity can affect how a clinician interprets the number.
Use waist measurements, body fat estimates, blood pressure, laboratory results, fitness, and medical guidance when they are available. For physique goals, the body fat and FFMI calculators provide information that BMI intentionally leaves out.
Track trends under similar conditions. A meaningful long-term change can be informative even when the category remains the same.
Questions people ask
