Anorexic BMI Health Calculator

    Anorexic BMI Calculator

    Calculate BMI and assess eating disorder indicators - Seek professional help

    Personal Information

    Anorexia commonly affects ages 16-26

    ~90% of cases are female

    Height

    Weight

    MD: Reviewed by a licensed physician. Last reviewed: March 2025. This page is for informational purposes only and does not constitute professional financial or medical advice.

    This calculator shows whether a BMI falls into the range associated with severe underweight or anorexia nervosa, which is a BMI below 17.5. It is a screening tool only. A healthcare professional must evaluate any concerns about eating disorders or low body weight.

    BMI Thresholds for Underweight

    The World Health Organization defines a BMI below 18.5 as underweight and a BMI below 17.5 as a clinical indicator often associated with anorexia nervosa. Severe underweight is classified at BMI below 16. These thresholds help clinicians identify patients who need nutritional assessment.

    BMI RangeClassification
    Below 16.0Severely underweight
    16.0 – 16.9Moderately underweight
    17.0 – 18.4Mildly underweight
    18.5 – 24.9Normal weight

    Limitations of BMI for Eating Disorder Assessment

    BMI is one data point in eating disorder diagnosis. Clinicians also assess psychological factors, eating behaviors, vital signs, and lab results. Someone can have an eating disorder at any BMI. If you are concerned about your eating behaviors or weight, speak with a doctor or mental health professional.

    Frequently Asked Questions

    What BMI is considered anorexic?

    A BMI below 17.5 is one clinical criterion associated with anorexia nervosa according to some diagnostic guidelines. However, diagnosis requires a full clinical assessment, not BMI alone.

    Is this calculator a medical diagnosis tool?

    No. This tool provides BMI information only. Eating disorder diagnosis requires evaluation by a qualified healthcare professional who assesses physical and psychological health together.

    What should I do if my BMI is very low?

    Contact a doctor as soon as possible. Severe underweight carries serious medical risks including heart problems, bone loss, and organ damage. Treatment is effective and recovery is possible with proper care.