BMI Calculator

The BMI Calculator computes your Body Mass Index — a widely used screening metric that relates your weight to your height to give a general indication of whether you fall into the underweight, normal, overweight, or obese category according to World Health Organization (WHO) standards. Enter your height and weight in either metric or imperial units, and the tool instantly returns your BMI value alongside the corresponding WHO classification. The formula is straightforward: BMI equals weight in kilograms divided by height in meters squared. Despite its simplicity, BMI remains the most commonly referenced population-level indicator in public health, clinical screenings, insurance assessments, and fitness baselines. The calculator also notes important context: BMI does not distinguish between muscle mass and fat mass, so athletes and individuals with high lean body mass may register as overweight despite having low body fat. For this reason, BMI is best used as an initial screening tool rather than a definitive health diagnosis. Combining it with waist circumference, body-fat percentage, or a clinical assessment gives a much fuller picture. The tool is useful for anyone tracking general weight trends over time, students learning about health metrics in biology or nutrition courses, healthcare workers performing quick population screenings, and fitness enthusiasts establishing a numeric baseline before starting a training program. You can switch freely between kilograms and centimeters or pounds and inches, and the result updates in real time as you adjust inputs. Every calculation runs locally inside your browser — your height and weight are never transmitted or stored on any server. There is no sign-up, no advertising, and no limit on how often you can use it. Check your BMI whenever you want a quick, private snapshot of where you stand on the standard weight-classification scale.

1. Enter your height and weight in metric or imperial units.
2. Read your BMI value instantly.
3. See which WHO category it falls into.
4. Use it as a quick screen, then consider body composition for the full picture.

BMI is a fast, standardized screen for weight-related health risk across a population. It's useful as a starting point, but it can't tell muscle from fat, so it's best read alongside other measures.

• Instant BMI from height and weight.
• WHO category ranges shown clearly.
• Metric and imperial units supported.
• A simple, widely understood health screening number.
• Everything is computed locally in your browser.

BMI = weight(kg) / height(m)². For imperial, BMI = 703 × weight(lb) / height(in)². WHO categories: under 18.5 is underweight, 18.5–24.9 is healthy, 25–29.9 is overweight, and 30 or above is obese. Because it uses only height and weight, BMI does not distinguish muscle from fat.