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BMI Calculator for Adults
Enter your height and weight to see your body mass index (BMI) and where it falls on the WHO adult ranges. BMI is a screening tool, not a diagnosis.
Calculate your BMI
This calculator runs in your browser. Nothing you enter is saved or sent anywhere.
How it works
BMI is your weight in kilograms divided by your height in meters squared.
The World Health Organization defines overweight in adults as a BMI of 25 or more, and obesity as a BMI of 30 or more. A BMI under 18.5 is classed as underweight, and the range between 18.5 and 24.9 is treated as healthy.
Limits of this tool
BMI does not measure muscle, body fat or where you carry weight, so it can mislead athletes and very muscular people. The WHO notes that other measures, such as waist circumference, can help. Some health bodies use different cut-offs for some ethnic groups. This tool is for adults only, not for children, teens or pregnancy. Ask a doctor to look at the whole picture.
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Questions
Frequently asked questions
For most adults, a BMI from 18.5 to 24.9 is treated as the healthy range. A BMI of 25 to 29.9 is classed as overweight, and 30 or more as obesity. It is a screening tool, not a diagnosis.
Not always. BMI does not separate muscle from fat, so a muscular person can have a high BMI without carrying extra body fat. Other measures, such as waist circumference, can add context.
No. For children and teens, BMI has to be compared with age and sex growth charts. A doctor or nurse can check a young person's growth.
The WHO notes that waist circumference can help. Blood pressure, blood sugar, cholesterol, fitness, energy and sleep also matter, and a doctor can check them.
Treat it as a prompt, not a verdict. Look at your habits, and speak to a doctor if you are worried, have a health condition, or are losing or gaining weight without trying.
Sources and further reading
- World Health Organization: Obesity and overweight fact sheet
- World Health Organization: Body mass index (BMI)
- NIDDK (NIH): Health risks of overweight and obesity
- NHS: Calculate your body mass index
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This tool is educational and is not medical advice. See our disclaimer.
Written by Dharshini Neelakandan and reviewed by Meena Narayanan, CPT. Read how we review.
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