What BMI is considered clinically anorexic?

In adults, a BMI below 17.5 is widely recognized as a physical indicator of anorexia nervosa. The DSM-5 defines severity as: Mild (BMI ≥ 17), Moderate (BMI 16–16.99), Severe (BMI 15–15.99), and Extreme (BMI < 15).

Can BMI alone diagnose anorexia nervosa?

No. BMI is solely a physical metric. Anorexia nervosa is a psychiatric and psychological condition diagnosed through comprehensive medical exams, behavioral assessments, and evaluation of body image perception.

What should someone do if their BMI is under 17.5?

Anyone with a BMI below 17.5 should seek evaluation from a healthcare professional, physician, or eating disorder specialist. Helplines such as NEDA (1-800-931-2237) offer confidential support.

Fitness

↵ to calculate

Anorexic BMI Calculator — Clinical Eating Disorder Screening

Free clinical BMI calculator assessing body mass index thresholds used by clinicians and the DSM-5 to indicate anorexia nervosa and severe underweight categories.

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How to use this calculator

👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉

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In plain English — what does this do?

🏋️ Your body needs food to move, breathe, and grow — just like a car needs petrol. This tool helps you find out how much food your body needs in a day to feel good and stay healthy!

📌 Direct Answer & Summary

The Anorexic BMI Calculator compares an individual's Body Mass Index (BMI) against clinical thresholds established by the World Health Organization (WHO) and the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) used in screening for anorexia nervosa and severe malnutrition.

Height

Weight (lbs)

Age

Biological Sex

Medical Disclaimer: This tool is designed strictly for educational screening based on statistical BMI classifications. It cannot provide a psychiatric or physical diagnosis of Anorexia Nervosa. If you or someone you care about is experiencing disordered eating, please consult a qualified healthcare professional or contact the National Eating Disorders Helpline at 1-800-931-2237.

What is Anorexic BMI Calculator — Clinical Eating Disorder Screening?

How to use it

1️⃣ Select your measurement system (US Units or Metric).
2️⃣ Enter your age, sex, height, and current body weight.
3️⃣ Review your calculated Body Mass Index (BMI) and diagnostic classification.
4️⃣ Check the minimum healthy body weight threshold corresponding to a normal BMI of 18.5.

Formula

BMI = Weight (kg) / [Height (m)]² or BMI = [Weight (lbs) × 703] / [Height (inches)]².

💡 See it in action — a real example

A 5'6" (66 inches) adult weighing 95 lbs: BMI = (95 × 703) / (66 × 66) = 15.33. This falls into the DSM-5 'Severe Anorexia' tier (BMI 15.0–15.99), requiring clinical intervention.

❓ Common questions

What BMI is considered clinically anorexic?: In adults, a BMI below 17.5 is widely recognized as a physical indicator of anorexia nervosa. The DSM-5 defines severity as: Mild (BMI ≥ 17), Moderate (BMI 16–16.99), Severe (BMI 15–15.99), and Extreme (BMI < 15).
Can BMI alone diagnose anorexia nervosa?: No. BMI is solely a physical metric. Anorexia nervosa is a psychiatric and psychological condition diagnosed through comprehensive medical exams, behavioral assessments, and evaluation of body image perception.
What should someone do if their BMI is under 17.5?: Anyone with a BMI below 17.5 should seek evaluation from a healthcare professional, physician, or eating disorder specialist. Helplines such as NEDA (1-800-931-2237) offer confidential support.