Calculate your Body Mass Index (BMI) using metric or imperial units. Understand your weight category and health implications.
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BMI = weight(kg) / height(m)²BMIBody Mass IndexweightBody weight in kilogramsheightHeight in metersBMI is a simple screening tool that uses height and weight to estimate body fat. It was developed by Belgian mathematician Adolphe Quetelet in the 1830s. While widely used, BMI has limitations - it does not distinguish between muscle and fat mass, and may be less accurate for athletes, elderly individuals, and certain ethnic groups.
Body Mass Index (BMI) is the most widely used screening tool for assessing whether a person has a healthy body weight relative to their height. Developed in the 19th century and adopted globally by health organizations, BMI provides a quick, non-invasive way to categorize weight status and identify potential health risks associated with being underweight, overweight, or obese.
Select your preferred unit system (metric or imperial), enter your weight and height, and the calculator instantly computes your BMI, weight category, healthy weight range for your height, and how much weight you would need to lose or gain to reach the healthy range.
An adult of average height and weight, using metric units.
BMI 22.9 — in the 'normal weight' range (18.5–24.9).
At this height, the healthy weight range is about 57–76 kg.
Same height, higher weight.
BMI 29.4 — in the 'overweight' band (25–29.9), just below the obese threshold.
BMI doesn't distinguish muscle from fat, so very muscular people can read 'overweight' while being lean — use it as a screening tool, not a diagnosis.
This calculator provides not just your BMI but also actionable context - your healthy weight range and the weight difference needed to reach it. This makes it a practical tool for setting realistic health goals and tracking progress over time.
A common mistake is interpreting BMI as a direct measure of body fat or health. BMI is a screening tool, not a diagnostic measure. Athletes with high muscle mass may have a high BMI while being perfectly healthy. Always interpret BMI in the context of your overall health picture.
Calculate your Basal Metabolic Rate (BMR) and daily calorie needs based on activity level using the Mifflin-St Jeor equation.
Calculate daily calorie needs for weight loss, maintenance, or muscle gain based on your goals and activity level.
Estimate body fat percentage using the US Navy method with waist, neck, and hip measurements. More accurate than BMI for body composition.