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Understand your body mass index with a simple reference for your weight and goals.
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Classification
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BMI is a useful starting point for assessing body weight, but it does not replace professional assessment.
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Beyond the number
These ranges are general references for adults. Children, teenagers, pregnant people and older adults need specific criteria. BMI does not distinguish muscle from fat or determine your health on its own.
BMI below 18.5
Your weight is below the reference range for your height. This does not confirm undernutrition: diet, weight history and health need to be assessed.
When undernutrition is also present, it can lead to muscle loss, weakness and greater susceptibility to infections. Unintentional weight loss warrants assessment.
BMI from 18.5 to less than 25
Your weight falls within the reference range for your height. Interpret the result alongside habits, body composition and health history.
In general, risks associated with excess weight are lower in this range. This does not rule out diabetes, high blood pressure or other health conditions.
BMI from 25 to less than 30
Your weight is above the reference range. BMI does not distinguish fat from muscle; waist measurement and clinical assessment help interpret the result.
There may be a higher risk of type 2 diabetes, high blood pressure and cardiovascular disease, particularly with excess abdominal fat.
BMI from 30 to less than 35
Your BMI falls in the first obesity category. Professional assessment helps clarify body composition and possible associated conditions.
The risk of weight-related conditions is elevated, including type 2 diabetes, high blood pressure and cardiovascular disease. Individual risk varies.
BMI from 35 to less than 40
Your BMI falls in the second obesity category. Care should consider your health history and individual needs.
The risk of weight-related conditions is very elevated. Assessing type 2 diabetes, blood pressure and cardiovascular health is an important part of care.
BMI of 40 or above
Your BMI falls in the third obesity category. Seek individual assessment and ongoing support from a healthcare team.
This range has the highest level of risk for weight-related conditions, such as type 2 diabetes and cardiovascular disease. BMI alone does not determine which conditions a person has.
Increased risk is not a diagnosis. An individual assessment also considers waist measurements, tests, age and health history.
Sources: Brazilian Ministry of Health — overweight and obesity in adults (Portuguese, new tab) and MSD Manual — undernutrition (Portuguese, new tab) .
Understand your tool
Body mass index divides weight in kilograms by height in meters squared: BMI = weight ÷ height². For example, 70 kg and 1.75 m give approximately 22.9 kg/m². Check your units before interpreting the category.
Reference: CDC — Adult BMI ↗Here to help
No. It only uses weight and height and cannot separate fat, muscle and bone. Interpretation depends on other health information.
No. Children and teenagers need criteria that account for age and sex. This tool shows general adult reference categories.
