BMI Calculator
Enter your weight and height and your BMI appears instantly. The calculation happens inside your browser and no data is sent or stored.
Enter a weight and a height to see your result.
Results are estimates. Solvemis accepts no responsibility for the results obtained or for how they are used. Always double-check the result and talk to a qualified professional before making decisions.
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How it works
How to use it
- Enter your weight in kilograms (kg). Use a point (.) for decimals.
- Enter your height in centimetres (cm).
- Your BMI and category appear as soon as you type, with no button to press.
How it is calculated
BMI is weight (kg) divided by height (m) squared. The categories follow the Korean Society for the Study of Obesity's clinical practice guidelines (2022): underweight below 18.5, normal under 23, pre-obesity under 25 and obesity from 25.
BMI = weight (kg) ÷ height (m)²
Sources
- 비만 진료지침 2022 (제8판) 요약본 — Korean Society for the Study of Obesity
- Obesity and overweight (fact sheet) — World Health Organization
About this calculator
What BMI is
BMI is an index of the relationship between weight and height, worked out by dividing weight (kg) by height (m) squared. At 70 kg and 1.75 m, it is 70 ÷ (1.75 × 1.75) = 22.9.
The categories
| BMI | Category |
|---|---|
| below 18.5 | Underweight |
| 18.5 to under 23 | Normal |
| 23 to under 25 | Pre-obesity |
| 25 to under 30 | Obesity, class 1 |
| 30 to under 35 | Obesity, class 2 |
| 35 and above | Obesity, class 3 |
The World Health Organization’s international criteria treat 25 and above as overweight and 30 and above as obesity. The Korean Society for the Study of Obesity uses lower thresholds because Asians, including Koreans, face a higher risk of related conditions such as diabetes at lower BMIs. This calculator uses the Korean criteria.
What BMI tells you and what it doesn’t
BMI is simple and easy to compare, but it doesn’t tell you what your weight is made of. It can’t separate muscle from fat or show where fat is stored. Visceral fat around the abdominal organs has a much bigger effect on the metabolism than fat under the skin.
So people with a lot of muscle can be classed as obese even with a low body fat percentage. Waist circumference is an extra measure you can take at home: 90 cm or more for men and 85 cm or more for women is considered abdominal obesity.
This result is for reference and is not a diagnosis. If you are worried about your health, talk to a medical professional.
Frequently asked questions
What is a normal BMI?
By the Korean Society for the Study of Obesity criteria, 18.5 to under 23 is normal. Below 18.5 is underweight, 23 to under 25 is pre-obesity and 25 or more is obesity.
Updated October 1, 2026
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