Understand your result
What is BMI?
Body mass index (BMI) is a quick screening measure that compares your weight with your height. It turns those two measurements into a single number that can be checked against broad weight categories.
BMI does not diagnose health on its own, but it can be a useful starting point for a conversation about weight and wellbeing.
For most adults, a BMI between 18.5 and 24.9 is described as the healthy range.
How do you calculate BMI?
Divide weight in kilograms by height in meters squared:
For example, a person who weighs 70 kg and is 1.75 m tall has a BMI of 22.9.
Adult BMI ranges
| Category | BMI range | General interpretation |
|---|---|---|
| Underweight | Below 18.5 | Below the standard healthy range |
| Healthy weight | 18.5–24.9 | Within the standard healthy range |
| Overweight | 25.0–29.9 | Above the standard healthy range |
| Obesity | 30.0 or above | Significantly above the standard range |
Things BMI cannot tell you
BMI does not distinguish body fat from muscle, bone, or water. Athletic adults, older adults, pregnant people, and children may need a different or more complete assessment.
This calculator is for general education and is not medical advice. A qualified healthcare professional can interpret your result in the context of your overall health.
Frequently asked questions
What is a healthy BMI?
For most adults, the commonly used healthy BMI range is 18.5 to 24.9.
Does BMI change with age?
Adult BMI categories do not change by age, but BMI interpretation for children and teenagers uses age- and sex-specific percentiles.
Is BMI different for men and women?
The basic adult BMI formula and categories are the same. Body composition can still differ, which is one reason BMI is only a screening measure.