Calculate Your Body Mass Index (BMI)
Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women.
BMI Categories:
- Severe Thinness – < 16
- Mild Thinness – 17 to 18.5
- Overweight – 25 to 30
- Obese Class II – 35 to 40
- Moderate Thinness – 16 to 17
- Normal – 18.5 to 25
- Obese Class I – 30 to 35
- Obese Class III – 40
BMI
Underweight
Being underweight may weaken your immune system and put you at risk of osteoporosis. Let’s talk what we can do to achieve a healthier weight or to address unexpected weight loss. For better health:
- Embrace healthy eating by choosing a variety of nutrient-rich foods, including fruits, vegetables and whole grains, and energy-dense foods like olive oil, nuts and dried fruits.
- Eat between-meal healthy snacks whole-grain crackers and nuts, for example to increase calories.
- Exercise. Your doctor may recommend strength training to promote lean muscle development and increase your weight in a healthy way.
Normal
Congratulations! Your healthy weight is well worth the effort. It reduces your risk of serious health conditions such as high blood pressure, heart disease, stroke and diabetes. To maintain a healthy weight:
- Embrace healthy eating by choosing a variety of nutrient-rich foods, including fruits, vegetables and whole grains, and small amounts of energy-dense foods like olive oil, nuts and dried fruits.
- Exercise. Aim for 30 to 60 minutes of moderately intense activity daily.
- Set action goals focused on specific healthy activities such as improving muscle tone through strength training or starting a daily food and activity diary.
Overweight
Consider the benefits of a healthy weight — a reduced risk of heart disease, stroke and diabetes, increased energy and improved self-esteem, for example. Let’s talk about the best weight-loss approach for you. To start:
- Embrace healthy eating by choosing a variety of nutrient-rich foods, including fruits, vegetables and whole grains, and small amounts of energy-dense foods like olive oil, nuts and dried fruits.
- Exercise. Ask your doctor about the right type of activities for you. Remember, even small amounts of activity provide immediate benefits.
- Set action goals focused on specific healthy activities such as starting a daily food and activity diary.
Obese
Let’s talk immediately and chalk out a plan to drastically improve your health!
What is BMI?
BMI is a measurement of a person’s leanness or corpulence based on their height and weight, and is intended to quantify tissue mass. It is widely used as a general indicator of whether a person has a healthy body weight for their height. Specifically, the value obtained from the calculation of BMI is used to categorize whether a person is underweight, normal weight, overweight, or obese depending on what range the value falls between. These ranges of BMI vary based on factors such as region and age, and are sometimes further divided into subcategories such as severely underweight or very severely obese. Being overweight or underweight can have significant health effects, so while BMI is an imperfect measure of healthy body weight, it is a useful indicator of whether any additional testing or action is required. Refer to the table below to see the different categories based on BMI that is used by the calculator.
Limitations of BMI
Although BMI is a widely used and useful indicator of healthy body weight, it does have its limitations. BMI is only an estimate that cannot take body composition into account. Due to a wide variety of body types as well as distribution of muscle, bone mass, and fat, BMI should be considered along with other measurements rather than being used as the sole method for determining a person’s healthy body weight.
In adults:
BMI cannot be fully accurate because it is a measure of excess body weight, rather than excess body fat. BMI is further influenced by factors such as age, sex, ethnicity, muscle mass, and body fat, and activity level, among others. For example, an older person who is considered a healthy weight, but is completely inactive in their daily life may have significant amounts of excess body fat even though they are not heavy. This would be considered unhealthy, while a younger person with higher muscle composition of the same BMI would be considered healthy. In athletes, particularly bodybuilders who would be considered overweight due to muscle being heavier than fat, it is entirely possible that they are actually at a healthy weight for their body composition. Generally, according to the CDC:
- Older adults tend to have more body fat than younger adults with the same BMI.
- Women tend to have more body fat than men for an equivalent BMI.
- Muscular individuals and highly trained athletes may have higher BMIs due to large muscle mass.
In children and adolescents:
The same factors that limit the efficacy of BMI for adults can also apply to children and adolescents. Additionally, height and level of sexual maturation can influence BMI and body fat among children. BMI is a better indicator of excess body fat for obese children than it is for overweight children, whose BMI could be a result of increased levels of either fat or fat-free mass (all body components except for fat, which includes water, organs, muscle, etc.). In thin children, the difference in BMI can also be due to fat-free mass.
That being said, BMI is fairly indicative of body fat for 90-95% of the population, and can effectively be used along with other measures to help determine an individual’s healthy body weight.