loot.tools

BMI Calculator

Enter your height and weight in metric (cm, kg) or imperial (feet/inches, lb) and get your BMI along with the WHO category - underweight, normal, overweight, or obese. It also shows the healthy weight range for your height so you have a concrete target rather than a single number. Everything runs in your browser, so nothing you type is sent anywhere.
Math

Enter a height and weight to see your BMI.

BMI is a rough screening number, not a diagnosis. It doesn't account for muscle mass, build, age, or sex, so athletes and older adults can land in a band that doesn't match their actual health. Treat it as a starting point and talk to a clinician for anything that matters.

What this tool does

Pick metric or imperial, type in your height and weight, and the calculator returns your BMI to one decimal place and the band it falls into. It also works out the weight range that would put you in the normal band for your height, so you can see how far off you are in actual kilograms or pounds rather than abstract BMI points.

How BMI is calculated

BMI is your weight in kilograms divided by your height in metres squared. Imperial inputs are converted to metric first, so a 5 foot 9, 154 pound person and a 175 cm, 70 kg person get the same answer. The WHO adult bands are: under 18.5 is underweight, 18.5 to 25 is normal, 25 to 30 is overweight, and 30 or above is obese.

What BMI doesn't tell you

BMI is a quick screening number, not a diagnosis. It only looks at height and weight, so it can't tell muscle from fat. A lean, muscular athlete can read as overweight, and the same BMI can mean different things at different ages or for different builds. Use it as a rough starting point and talk to a clinician for anything that actually matters.