What is BMI and Why Calculate It?
The Body Mass Index (BMI) is a simple measure used by the World Health Organization (WHO) to assess whether your weight is appropriate for your height. It is calculated by dividing weight (in kg) by height squared (in meters).
Although it does not account for muscle mass, age, or sex (for adults), BMI is a quick and widely accepted reference for identifying health risk categories.
WHO Classification Ranges (adults over 20 years): – Below 18.5 → Underweight – 18.5 to 24.9 → Normal (healthy) – 25.0 to 29.9 → Overweight – 30.0 or higher → Obesity
Use our free calculator below to find out your BMI in seconds. 100% online, no signup required!
Free BMI Calculator Online
Enter your weight and height to calculate your Body Mass Index (BMI) according to the World Health Organization (WHO). Simple, fast, and 100% free!
| BMI | Classification (WHO) |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity Class I |
| 35.0 – 39.9 | Obesity Class II |
| 40.0 or higher | Obesity Class III |
Done! Now you know your BMI and which category you fall into.
Quick Health Tips: – Normal BMI (18.5–24.9) → maintain healthy habits. – Overweight or obesity → consult a nutritionist or doctor. – Remember: BMI is just one indicator. Always consult a professional to assess body composition, body fat percentage, and overall health.
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