Calculator
BMI Chart
Use an interactive adult BMI reference chart to understand BMI ranges, category boundaries, examples, and the difference between screening and diagnosis.
Check a BMI value
Chart result
Adult BMI reference chart
This chart is intended to answer a different question from a calculator: where does a BMI value sit within the adult screening categories? Enter a value above to see the category highlighted.
| Category | BMI range | What the label means |
|---|---|---|
| Underweight | Below 18.5 | A screening category below the standard adult healthy-weight range. |
| Healthy weight | 18.5 to <25 | The standard adult BMI range used for this screening category. |
| Overweight | 25 to <30 | A screening category above the healthy-weight range and below 30. |
| Obesity class 1 | 30 to <35 | First adult obesity class. |
| Obesity class 2 | 35 to <40 | Second adult obesity class. |
| Obesity class 3 | 40 or greater | Third adult obesity class. |
How to read the chart
Find the calculated BMI on the horizontal scale and identify the category containing it. A BMI of 24.9 and a BMI of 25.0 sit on different sides of a category boundary, even though the numerical difference is small. This is one reason a category should be treated as a screening label rather than a precise biological switch.
Calculation
BMI is weight divided by height squared. The chart assumes the BMI has already been calculated correctly.
Interpretation
Adult categories are standard screening ranges for adults 20 and older.
Context
BMI does not directly measure body fat, muscle mass, or fat distribution.
BMI is not the same as body fat
Two people can have the same BMI while having different body-fat percentages and different muscle mass. Conversely, two people with different BMI values can have similar body-fat levels. If body composition is the question, a body-fat estimate or another validated assessment can provide different information. See the Body Fat Calculator for an educational estimate.
Age and BMI
For adults, the standard screening categories do not change simply because someone is older. For children and teenagers, however, BMI must be interpreted relative to age and sex because body composition changes during growth. See BMI Calculator by Age and BMI Calculator for Children.
Frequently asked questions
What BMI range is called healthy weight?
For adults 20 and older, 18.5 to less than 25 kg/m² is the standard healthy-weight screening category.
What does a BMI of 30 mean?
A BMI of 30 falls at the beginning of the adult obesity category. The category is a screening classification, not a diagnosis.
Does the adult chart apply to children?
No. Pediatric BMI is interpreted using age- and sex-specific BMI-for-age references.
Why are there category boundaries?
Boundaries create standardized screening groups. They should not be interpreted as abrupt biological changes at a single decimal point.
Can BMI tell me my body-fat percentage?
No. BMI cannot directly determine body-fat percentage.
Does sex change adult BMI thresholds?
The standard adult BMI category thresholds do not have separate male and female versions.
Why might an athlete have a high BMI?
Muscle is dense tissue, so substantial muscularity can increase weight and therefore BMI.
Is a BMI chart enough to assess health?
No. Health assessment can include many additional measures and individual factors.