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✦ ADULT BMI CATEGORY GUIDE
Adult BMI Weight Categories
Understand adult BMI categories and ranges, including underweight, healthy weight, overweight and obesity. Explore BMI chart values and what your BMI result means.
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✦ What You’ll Learn
Adult BMI categories group calculated BMI values into broad screening ranges. They can help start a conversation about weight-related health, but they cannot diagnose a condition or describe every person's health.
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Adult BMI category chart
The commonly used adult screening categories are: below 18.5 is underweight; 18.5–24.9 is the healthy-weight range; 25.0–29.9 is overweight; and 30.0 or above is the obesity range.
These cut-offs are general adult references. Interpretation may differ in some populations and clinical settings.
Underweight: BMI below 18.5
A BMI below 18.5 is classified as underweight in the standard adult framework. It does not explain why a person has a lower weight. Recent unintentional weight loss, low appetite or other symptoms deserve professional assessment.
A clinician can help consider nutrition, medical history and possible causes rather than relying on BMI alone.
Healthy weight range: BMI 18.5–24.9
This range is commonly used as a general adult reference. Being within it does not guarantee good health, and being outside it does not by itself establish poor health.
Consider other factors such as waist measurement, blood pressure, activity, nutrition, sleep and medical history.
Overweight: BMI 25.0–29.9
This range is above the standard adult healthy-weight reference. BMI is a screening signal, not a judgement. Muscle mass, body composition and individual risk factors can affect how the number should be interpreted.
A healthcare professional can help assess whether additional checks or lifestyle support are appropriate.
Obesity range: BMI 30 or above
A BMI of 30 or above falls in the standard adult obesity range. This classification is not a complete assessment of health or an individual diagnosis.
Discuss your result with a qualified healthcare professional who can consider other measurements, health conditions and suitable support.
BMI categories for children and teenagers
For people aged 2–19, BMI is interpreted using age- and sex-specific percentiles rather than adult cut-offs. Growth and development must be considered.
Use a suitable child or teen BMI assessment and consult a paediatric healthcare professional when needed.
Health information notice: BMI is a screening measure, not a diagnosis. This guide provides general educational information and does not replace advice from a qualified healthcare professional.
? Frequently Asked Questions
What are the four adult BMI categories?
The common categories are underweight, healthy weight range, overweight and obesity range.
Is BMI 25 overweight?
In the standard adult framework, a BMI of 25.0 begins the overweight range.
Is BMI 30 considered obesity?
A BMI of 30.0 or above is within the standard adult obesity range.
Are BMI categories the same for men and women?
The standard adult cut-offs are generally the same, but BMI does not capture every difference in body composition.
Can BMI categories diagnose a health condition?
No. BMI is a screening measure and must not be treated as a diagnosis.
Adult BMI category keywords
Adult BMI categories are commonly grouped as underweight, healthy weight, overweight and obesity. These ranges help adults interpret a BMI result, but they do not measure body fat directly and should be considered alongside other health information. Children and teenagers require age- and sex-specific BMI assessment.
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