BMI Calculator

How to Use

Enter your height in centimeters and weight in kilograms. Your BMI, category, and healthy weight range are calculated instantly.

About BMI

BMI (Body Mass Index) is a simple numeric measure derived from your height and weight. The formula is: BMI = weight (kg) / height (m)². For example, a person who weighs 70 kg and stands 1.75 m tall has a BMI of 22.9. The World Health Organization (WHO) classifies BMI into four categories: Underweight (below 18.5), Normal weight (18.5 to 24.9), Overweight (25.0 to 29.9), and Obese (30.0 and above). These thresholds were established based on epidemiological data linking BMI ranges to health risk levels. BMI is widely used in public health as a quick screening tool, though it should be interpreted alongside other health indicators.

Use Cases

• Health checkups — quickly assess whether your weight falls within a healthy range during routine medical visits.
• Fitness tracking — monitor weight changes over time and evaluate progress toward a target body composition.
• Clinical screening — healthcare providers use BMI as a first-pass indicator to identify patients who may benefit from further nutritional or metabolic assessment.

Limitations

BMI is a useful screening metric, but it has well-known limitations. It does not distinguish between muscle mass and fat mass, so muscular athletes may be classified as overweight despite having low body fat. BMI also does not account for differences in body composition related to age, sex, or ethnicity — for instance, BMI cut-offs may underestimate health risk in certain Asian populations. It is not designed for use with children, pregnant women, or the elderly, who require age- or condition-specific growth charts and assessments. For a complete picture of health, BMI should be used alongside other measurements such as waist circumference, body fat percentage, and clinical evaluation.

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