Severe Underweight & Thinness Calculator
Calculates BMI and Ponderal Index (PI) to screen for malnutrition risk.
Enter weight in kilograms (kg).
Enter height in centimeters (cm).
Required for accurate risk assessment.
Body Mass Index (BMI)
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Ponderal Index (PI)
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Understanding Severe Underweight Status
This tool calculates two key metrics used to classify **severe thinness** and malnutrition risk: **Body Mass Index (BMI)** and **Ponderal Index (PI)**. While BMI is the standard, PI is often considered more precise for individuals at the extreme low or high ends of the height spectrum.
BMI Calculation & Staging
$$BMI = \frac{\text{Weight (kg)}}{\text{Height (m)}^2}$$
- **Normal:** $18.5 – 24.9$
- **Mild Thinness:** $17.0 – 18.49$
- **Moderate Thinness:** $16.0 – 16.99$
- **Severe Thinness:** Below $16.0$
Ponderal Index (PI) Calculation
$$PI = \frac{\text{Weight (kg)}}{\text{Height (m)}^3}$$
A typical healthy PI for an adult is around **$12$ to $14$**. Values significantly lower than this suggest severe lack of body mass relative to height.
Important Medical Disclaimer
**This tool is NOT a diagnostic aid for Anorexia Nervosa (AN) or any other eating disorder.** Eating disorders are severe psychiatric illnesses. If you or someone you know is struggling with weight, body image, or eating habits, please seek professional medical or psychological help immediately.