ICD-10 Code E66.811 – Obesity, class 1 (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E66.811 – Obesity, class 1
What it is
Code E66.811 identifies class 1 obesity, a clinical diagnosis of excess body weight in the mild obesity range. Use it when the record specifically documents class 1 obesity.
Clinical signs
Clinical features vary; refer to documentation. Obesity is usually recognized by a documented elevated body mass index and clinician assessment of excess adiposity.
When to use this code
Use E66.811 when the provider documents class 1 obesity without a more specific obesity type. It may appear in routine visits, problem lists, or assessments tied to counseling or risk review. Code only when the diagnosis is clearly stated in the chart.
Do not use for
Do not use this code for overweight, unspecified obesity, or obesity class 2 or 3. If the documentation does not specify class 1 obesity, check documentation.
Coding tip
Assign E66.811 only when the provider explicitly documents class 1 obesity; do not infer the class from body mass index alone.