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ToolWrenCalculate your Body Mass Index from your height and weight, in metric or imperial units, and see which standard category the result falls into.
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BMI is a free, private online tool that lets you calculate your Body Mass Index (BMI) in metric or imperial units and see the standard weight category. It runs entirely in your browser, so nothing you enter is uploaded to a server.
Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.
Body Mass Index is a simple ratio of weight to height (kg/m²) used as a quick screening measure for weight categories. It's widely used by health organisations as a first indicator.
The standard ranges are: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30+ obese. This tool labels your result automatically.
BMI doesn't distinguish muscle from fat or account for body composition, so very muscular people may read as "overweight". Use it as a general guide, not a diagnosis.
Body Mass Index (BMI) is a simple ratio of weight to height used as a quick screening measure for whether someone is a healthy weight. It is calculated from just two numbers and gives a single figure that maps onto standard categories - underweight, normal, overweight and obese - which is why health services use it as a first-line indicator.
The formula is weight in kilograms divided by height in metres squared (kg/m2). In imperial units it is 703 x weight in pounds / height in inches squared. So someone 1.75 m tall weighing 70 kg has a BMI of 70 / (1.75 x 1.75) = 22.9. This calculator works in both metric and imperial so you can use whichever you know.
The standard adult BMI ranges are: under 18.5 = underweight, 18.5 to 24.9 = normal (healthy) weight, 25 to 29.9 = overweight, and 30 or above = obese. These thresholds come from population studies linking BMI to health risk, and the tool labels your result automatically so you can see where it falls.
BMI is a blunt instrument. Because it uses only height and weight, it cannot distinguish muscle from fat - so very muscular athletes can register as overweight despite low body fat. It also does not account for fat distribution, age, sex or ethnicity, all of which affect health risk. Use it as a general guide, not a diagnosis; waist measurement and body-fat percentage add useful context.
Get a quick read on whether your weight is in a healthy range, track changes over time, and decide whether to look deeper with other measures. For personalised advice, especially if you are very active, pregnant, elderly or have health conditions, consult a professional. Everything is calculated in your browser.