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  6. 2026 ICD-10-CM Code E66

2026 ICD-10-CM Diagnosis Code E66

Overweight and obesity

ICD-10-CM Code:
E66
ICD-10 Code for:
Overweight and obesity
Is Billable?
Not Valid for Submission
Code Navigator:

E66 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of overweight and obesity. The code is not specific and is NOT valid for the year 2026 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Overweight and obesity

Non-specific codes like E66 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for overweight and obesity:

  • E66.0 for Obesity due to excess calories - NON-BILLABLE CODE

  • Use E66.01 for Morbid (severe) obesity due to excess calories - BILLABLE CODE

  • Use E66.09 for Other obesity due to excess calories - BILLABLE CODE

  • Use E66.1 for Drug-induced obesity - BILLABLE CODE

  • Use E66.2 for Morbid (severe) obesity with alveolar hypoventilation - BILLABLE CODE

  • Use E66.3 for Overweight - BILLABLE CODE

  • E66.8 for Other obesity - NON-BILLABLE CODE

  • E66.81 for Obesity class - NON-BILLABLE CODE

  • Use E66.89 for Other obesity not elsewhere classified - BILLABLE CODE

  • Use E66.9 for Obesity, unspecified - BILLABLE CODE

Code Classification

  • Endocrine, nutritional and metabolic diseases
    E00–E89
    • Overweight, obesity and other hyperalimentation
      E65-E68
      • Overweight and obesity
        E66

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Code First

Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
  • obesity complicating pregnancy, childbirth and the puerperium, if applicable O99.21

Use Additional Code

Use Additional Code
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.

Type 2 Excludes

Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
  • adiposogenital dystrophy E23.6
  • lipomatosis dolorosa Dercum E88.2
  • lipomatosis NOS E88.2
  • Prader-Willi syndrome Q87.11

Patient Education


Body Weight

What is body weight?

Body weight is the total mass of your body. Keeping track of your weight is one way to check for changes in your health, but it can't tell you the whole story. That's because your weight includes muscle, bone, fat, and water. Also, everyday factors can play a role in your weight, such as your:

  • Diet
  • Activity level
  • Stress level
  • Sleep habits
  • Family history and genetics
  • Age

What factors help determine a healthy body weight?

A healthy weight is more than just a number on the scale. It's about feeling good, having energy, and lowering your risk of disease. Your health care provider can help you determine a healthy body weight based on several factors. These include your:

  • Body Mass Index (BMI). BMI is a measure of how much you weigh compared to how tall you are. The higher your BMI, the higher your risk for certain diseases. BMI does not distinguish between fat, muscle, and bone mass. It also may overestimate body fat in athletes or those with a muscular build, or underestimate body fat in older persons or others who have lost muscle.
  • Waist circumference. If most of your body fat is around your abdomen (belly) rather than your hips, you may be at a higher risk for heart disease and type 2 diabetes.
  • Health history. Your health care provider will likely consider your risk factors for diseases and health conditions, such as having high cholesterol, in determining your healthy body weight.

What are body weight ranges?

Having a healthy body weight may lower your chance of developing certain health problems. Carrying too much or too little weight can affect your health. Ranges of body weight include:

  • Underweight. Your weight is lower than it should be for your health.
  • Normal. Your weight is within a healthy range.
  • Overweight. Your weight is greater than it should be for your health.
  • Obese. Your body fat is greater than it should be for your health.

Body weight needs can be different at different ages. For children, weight and growth are tracked over time based on their age. For older adults, keeping muscle and strength is key, and sudden weight loss should always be checked by your provider.

What if I have a sudden gain or loss of weight?

Talk to your provider if you're losing or gaining weight without trying. A sudden, unexpected change in weight can be a sign of a medical problem.

Causes for sudden weight loss can include:

  • Thyroid problems
  • Cancer
  • Infectious diseases
  • Digestive diseases
  • Certain medicines

Causes for sudden weight gain can include:

  • Certain medicines
  • Thyroid problems
  • Heart failure
  • Kidney disease
  • Liver disease

How can I maintain a healthy body weight?

Maintaining a healthy body weight can improve energy, sleep, and overall wellbeing. Talk to your provider about what a healthy weight would be for you. If they recommend that you gain or lose weight, they might refer you to a dietician for support. A dietician is a professional who has special training to help you learn the best way to eat.

  • Good nutrition and exercise can help in losing weight. Even a small change in weight can lower your risk of developing certain diseases.
  • Eating extra calories within a well-balanced diet and treating any underlying medical problems can help you gain weight.

Focus on your health, not just the number on the scale. With daily healthy habits and self-compassion, you can support lasting improvements in your overall wellbeing.

NIH: National Heart, Lung, and Blood Institute


[Learn More in MedlinePlus]

Obesity

What is obesity?

Obesity is a disease that means having too much body fat. It is different from being overweight, which means weighing too much. Both terms mean that your weight is greater than what's considered healthy for your height.

Body Mass Index (BMI) measures how much you weigh compared to how tall you are. An adult who has a BMI of 30 or more is considered to have obesity. Severe obesity is having a BMI of 40 or higher. Obesity increases your risk for many other diseases and health problems, especially if the extra body fat is carried around the waist.

What raises your risk of obesity?

Obesity happens over time from taking in more calories (through food and drinks) than used up from physical activity and daily living. Your body stores the extra calories as fat. The right balance between calories and activity is different for everyone.

There are many different factors that can affect your body weight. Certain medicines or medical conditions may affect your weight. Other factors include your:

  • Genetic makeup
  • Eating habits
  • Sex
  • Race or ethnicity
  • Physical activity level

How is obesity diagnosed?

To find out if you have obesity, your health care provider may:

  • Ask about your health history, which may include reviewing your weight history, weight-loss efforts, and how physically active you are.
  • Do a physical exam, which may include checking your height, weight, and vital signs, as well as listening to your heart and lungs.
  • Order blood tests or other imaging tests, which may include checking any known health problems, as well as for other weight-related diseases and health conditions.
  • Calculate your BMI, to check your risk for certain diseases. The higher your BMI, the higher your risk. BMI does not distinguish between fat, muscle, and bone mass. It may also overestimate body fat in athletes or those with a muscular build, or underestimate body fat in older persons, or others who have lost muscle.
  • Check your waist size, since a large waistline, with more body fat around your abdomen (belly) rather than your hips, increases your risk for weight-related health problems.

What health problems can obesity cause?

Having a larger body size can make your heart work harder, put extra pressure on your joints, and may increase your risk for many health conditions, including:

  • Type 2 diabetes.
  • Heart disease.
  • High blood pressure.
  • Stroke.
  • Metabolic syndrome.
  • Osteoarthritis.
  • Sleep apnea.
  • Pregnancy problems.
  • Fertility problems.
  • Some cancers.

If you have obesity, losing even 5 to 10% of your weight can delay or prevent some of these diseases. For example, that means losing 10 to 20 pounds if you weigh 200 pounds.

What are the treatments for obesity?

Treatment plans for obesity may depend on your overall weight, other health conditions, and your willingness to participate in a weight-loss plan.

Your provider can tell you what a healthy weight is for you, help you set goals, and give you tips on how to lose weight. They may refer you to other providers that specialize in nutrition or weight loss to help you make realistic goals and provide support.

Possible treatments may include:

  • Dietary changes and exercise goals to help you learn how to adopt healthy nutrition, exercise, and lifestyle changes to lose weight safely and keep it off long term.
  • Counseling or support groups can give you encouragement and help you understand what's behind weight changes.
  • Weight-loss medicines to treat obesity.
  • Weight loss procedures or surgery if you have severe obesity or serious obesity-related health problems and have not been able to lose enough weight.

A healthy lifestyle that includes healthy eating patterns and regular physical activity can help you lose weight and lower your chance of developing complications related to obesity.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases


[Learn More in MedlinePlus]

Food Portions: Choosing Just Enough for You

For a healthy weight, learn to read a Nutrition Facts label, understand how portions and servings differ, and choose the right amount of food for you.
[Learn More in MedlinePlus]

Code History

  • FY 2026 - No Change, effective from 10/1/2025 through 9/30/2026
  • FY 2025 - No Change, effective from 10/1/2024 through 9/30/2025
  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.