BMI Calculator
Calculate BMI (Body Mass Index) from height and weight and assess health risk
Inputs
cm
kg
BMI classification
What is BMI?
BMI (Body Mass Index) is a commonly used indicator based on height and weight to roughly assess weight status and related risks.
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
| BMI range | Category | Health risk |
|---|---|---|
| < 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.