A clear adult BMI chart, the formula behind it, and the limitations to remember before interpreting a BMI category.
Adult BMI categories
For adults, commonly used BMI categories group results into underweight, healthy weight, overweight and obesity, with obesity sometimes divided into classes. These categories are screening ranges, not a medical diagnosis.
How to read a BMI chart
Find the calculated BMI value and see which range contains it. The category describes a weight-to-height relationship. It does not tell you how much of the weight is muscle, fat, bone or water.
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The formula behind the chart
BMI equals weight in kilograms divided by height in metres squared. A chart is only a visual way of interpreting the number produced by that formula.
Why the same category can mean different things
Two people can share the same BMI and have different body composition, fitness, medical history and waist measurements. A highly muscular person may have a higher BMI without having the same body-fat level as another person.
Use the chart as a screening tool
The most responsible use of BMI is as one piece of information. If the result is unexpected or concerning, consider other health measures and professional advice rather than treating the category as a diagnosis.
Children need different references
Adult BMI categories should not be used for children and teenagers. Growth references consider age and sex because bodies change during development.
Official reference
CDC states that adult BMI is a screening measure and should be considered together with other health information.
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Frequently asked questions
What BMI is considered healthy for adults?
Common adult screening ranges usually place 18.5 to under 25 in the healthy-weight category, but local guidance and individual context matter.
Is BMI accurate for athletes?
It can be less informative because it does not distinguish muscle from fat.
Does BMI measure body fat?
No. It is a weight-to-height calculation.
Can BMI diagnose obesity-related disease?
No. It is a screening measure, not a diagnosis.
Should children use this chart?
No. Children and teens need age- and sex-specific references.
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