What BMI can and cannot tell you
BMI is a quick screening number that compares weight to height. It can help identify broad weight categories at a population level, but it does not directly measure body fat, muscle mass, bone density, waist circumference, pregnancy status, or health risk for a specific person.
How this calculator works
The calculator converts your height and weight to metric units and applies the standard adult BMI formula. It then places the number into the common adult category ranges. The page is written for adults and should not be used for children or teens, who require age- and sex-specific percentiles.
How to use the result
Use BMI as a first-pass signal, not a final answer. If your BMI is outside the normal range, consider waist size, activity, blood pressure, labs, medical history, and professional advice. Athletes, older adults, pregnant users, and people with high or low muscle mass may need more context.
Quick interpretation table
| Under 18.5 | Underweight screening range. |
| 18.5 to 24.9 | Normal adult BMI screening range. |
| 25.0 to 29.9 | Overweight screening range. |
| 30.0 and above | Obesity screening range, with higher classes above 35 and 40. |
Example result
A person who weighs 180 lb and is 70 in tall has a BMI near 25.8, which falls in the overweight screening range. That result does not prove the person has excess body fat, but it is a signal to look at waist size, training history, and health markers.