Adult BMI categories
| Category | BMI |
|---|---|
| Underweight | Below 18.5 |
| Healthy weight | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Obesity class 1 | 30.0–34.9 |
| Obesity class 2 | 35.0–39.9 |
| Obesity class 3 | 40.0 and above |
How should BMI be interpreted?
BMI is weight in kilograms divided by height in meters squared. It does not directly measure body-fat or muscle distribution.
It is more meaningful when considered alongside other information such as medical history, waist circumference, blood pressure, muscle mass and laboratory results.
Frequently Asked Questions
Can BMI replace a medical diagnosis?
No. BMI is a screening measure and cannot diagnose a condition or determine treatment on its own.
What age group is this calculator for?
It is intended for adults age 20 and older. Ages 2–19 require age- and sex-specific percentile assessment.
Why are calorie and body-fat results estimates?
The formulas do not directly measure metabolism or body fat; they produce statistical estimates from the inputs.
What BMI range is shown as the adult reference range?
The calculator uses the common adult screening range 18.5 ≤ BMI < 25 to show a mathematical reference-weight interval. It is not a personal treatment target.
Why can BMI be misleading for some people?
BMI does not distinguish fat from muscle and can be less informative during pregnancy, with high muscularity, edema, older age or certain medical conditions.
Important information
Pregnancy, high muscularity, edema, older age, certain medical conditions or major weight changes can limit how BMI should be interpreted.
If you have unexpected weight change, nutrition concerns or other health concerns, consult a qualified health professional.