TopToolAIBMI Calculator
BMI Calculator: a free BMI calculator for men, women, kids and teens, and Asians, all in one place. Enter your weight in kilograms and your height in centimeters, choose who the BMI is for, and instantly see your Body Mass Index, which BMI category you fall into (underweight, normal weight, overweight or obese), the full BMI chart for reference, your healthy weight range for your height and a practical suggestion for your result. BMI is worked out as weight in kilograms divided by height in metres squared: someone who weighs 70 kg and is 1.70 m tall has a BMI of 70 divided by (1.70 x 1.70), or 24.2, which falls in the normal BMI range of 18.5 to 24.9, while someone weighing 90 kg at 1.65 m comes out at 33.1, in the obese range of 30 and above. Choose adult man or adult woman for the standard adult BMI table with a note that fits you, the Asian option for the lower WHO action points of 23 and 27.5 used for Pakistan, India and other South Asian countries, or boy or girl (ages 2 to 19) to get a BMI percentile for children and teens from the CDC growth charts. The formula was devised in the 1830s by the Belgian mathematician Adolphe Quetelet as a population-level statistical measure, which is why it remains the standard quick screening tool used by doctors and health organisations worldwide today.
How to use BMI Calculator
Step-by-step guide to the boxes below. Open it only if you need help.
How to use BMI Calculator
Step-by-step guide to the boxes below. Open it only if you need help.
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1
Calculate for Choose one
Pick who you are checking: an adult man, an adult woman, an adult on the Asian / South Asian scale, a boy or a girl. Adults are read against the standard adult table, and the Asian option uses the lower WHO action points of 23 and 27.5. For a child or teenager the tool needs their age and compares them with other children of the same age and sex.
Choose one: Adult man (20+ years)Adult woman (20+ years)Adult, Asian / South Asian scale (20+ years)Boy (2–19 years)Girl (2–19 years)
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2
Weight (kg) Text
Type your weight in kilograms. If your scale shows pounds, divide by 2.2 first (150 lb is about 68 kg). Weigh yourself in the morning if you want a steady, comparable number.
Example: 70
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3
Height (cm) Text
Type your height in centimetres, not feet. Quick conversion: total inches x 2.54, so 5 ft 9 in (69 in) is about 175 cm. Stand straight without shoes when you measure.
Example: 175
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4
Age of child (years) Text
This box only appears for a boy or girl. Type the age in years, and add .5 if the child is six months past a birthday, so 9 years 6 months is 9.5. The tool covers ages 2 to 19.
Example: 9
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5
Press “Calculate BMI”
Click the button under the boxes. If something is missing or not valid, a short message tells you which box to fix.
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6
Read your result
You get your BMI number, the band it falls in (underweight, normal, overweight or obese) and a small table that shows where you stand. For a boy or girl you get a percentile for their age instead, with the category it falls in. Change any box and try again to compare different numbers.
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