BMI classification
Formula
BMI = weight (kg) ÷ height (m)²
If height is in cm: BMI = weight (kg) ÷ (height (cm)/100)²
This tool rounds to 1 decimal place
How to interpret the result
Underweight: pay attention to nutrition intake and diet structure; consult a professional if needed
Normal: maintain balanced diet and regular exercise; consider body fat and waist circumference for a fuller view
Overweight/Obese: reduce total calorie intake and increase activity; assess together with body fat percentage
Applicability & limitations
BMI reflects the ratio of weight to height and cannot distinguish fat from muscle
Athletes/high-muscle individuals may have a higher BMI without being obese
Pregnant people, children/teens, and older adults should use more appropriate standards
For weight management or chronic conditions, use BMI together with other metrics (waist, body fat %, etc.) and medical advice
Classification Table
- BMI range
- Category
- Health risk
Example Rows
< 18.5 - Underweight - Risk of malnutrition
18.5 - 23.9 - Normal - Low health risk
24 - 27.9 - Overweight - Mild health risk
≥ 28 - Obese - High health risk
FAQ
What's the difference between BMI and body fat percentage?
BMI uses height and weight to estimate weight status; body fat percentage reflects the proportion of fat mass. Using both provides a fuller picture.
Why do I look 'fat' even with a normal BMI?
It may be due to higher body fat percentage, lower muscle mass, or fat distribution. Consider checking waist circumference and body fat %.
Does a high BMI always mean unhealthy?
Not always. High-muscle individuals may have a high BMI. Consider other indicators such as waist, blood pressure, and labs.