BMI Calculator
Calculate body mass index and category.
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This tool processes everything locally in your browser. Nothing is uploaded to a server.
📝 About BMI Calculator
The BMI Calculator computes your Body Mass Index from your height in centimeters and weight in kilograms and shows which weight category the result falls into. The result updates as you type, with a color that changes by category.
BMI is calculated as weight (kg) ÷ height (m)². For example, a person who is 170 cm tall and weighs 65 kg has a BMI of 65 ÷ 1.7² ≈ 22.5. This tool uses the World Health Organization’s adult categories: under 18.5 is underweight, 18.5 to under 25 is normal, 25 to under 30 is overweight, and 30 or above is obese. Note that some Asian guidelines, including Korea’s, use lower cut-offs, treating 23 or above as overweight and 25 or above as obese.
BMI is a quick screening number, not a diagnosis. It does not distinguish muscle from fat, so athletes may score high, and it is not designed for children, teenagers or pregnant women. The result is for reference only and is not medical advice; consult a healthcare professional for an assessment of your health.
📘 How to use
- 1
Enter your height
Type your height in centimeters.
- 2
Enter your weight
Type your weight in kilograms.
- 3
Check your BMI
Your BMI and its category appear instantly below the inputs.
❓ FAQ
Which BMI categories does this tool use?
It uses the WHO adult categories: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30 or above obese.
Why does Korea use different BMI cut-offs?
Research shows Asian populations face higher health risks at lower BMI levels, so Korean guidelines treat 23 or above as overweight and 25 or above as obese.
Can I use pounds and inches?
The calculator accepts centimeters and kilograms only. You can convert pounds and inches first with the Unit Converter.
Is BMI accurate for everyone?
No. It cannot tell muscle from fat and is not meant for children, teens or pregnant women. Treat it as a reference and ask a doctor for a proper assessment.