ICD-10 code guides
Reviewed July 1, 2026

ICD-10 codes for obesity

Obesity coding requires both the clinical diagnosis and, when documented, the BMI category. E66.- codes describe obesity; Z68.- codes describe body mass index and are commonly added when BMI is recorded.

E66.9 billable

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ICD-10-CM

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Obesity ICD-10 codes

Start with the primary code, then move to a more specific related code when the documentation supports it.

CodeDescriptionSystem

E66.9

Obesity, unspecified

ICD-10-CM

E66.01

Morbid (severe) obesity due to excess calories

ICD-10-CM

E66.3

Overweight

ICD-10-CM

Z68.30

Body mass index 30.0-30.9, adult

ICD-10-CM

Z68.41

Body mass index 40.0-44.9, adult

ICD-10-CM

Z71.3

Dietary counseling and surveillance

ICD-10-CM

How to choose the right code

Code the documented weight diagnosis first: overweight, obesity, or severe obesity. Add the specific BMI Z68.- code when BMI is documented and payer rules allow it. Do not code BMI alone without the associated clinical diagnosis.

Documentation example

Weight-management visit. BMI 42.1 with hypertension and knee pain limiting exercise. Assessment: severe obesity due to excess calories. Discussed nutrition plan, GLP-1 eligibility, and referral to dietitian.

Suggested:

E66.01
Z68.41
Z71.3

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FAQ

Can I code BMI without obesity?

BMI Z68.- codes are secondary context codes and generally require the associated weight diagnosis to be documented.

When is E66.01 appropriate?

Use E66.01 when severe or morbid obesity due to excess calories is documented, often with BMI 40 or higher depending on clinical and payer context.

Can AI extract BMI and counseling facts?

Notat extracts BMI, obesity diagnosis, comorbidities, and counseling decisions as clinical facts, then suggests diagnosis and BMI codes with supporting evidence.

Related ICD-10 guides

Keep moving through the condition hub, or open the general medical coding guide for more coding systems and extractors.

Medical coding hub