Calculate your Body Mass Index (BMI) to determine your weight category. BMI is a simple calculation using a person's height and weight to assess if they have a healthy body weight.
Enter your height and weight to calculate your BMI and determine your weight category.
The following table shows the standard weight status categories associated with BMI ranges for adults.
| Category | BMI Range (kg/m²) | Risk Level |
|---|---|---|
| Underweight | Below 18.5 | Increased risk |
| Normal weight | 18.5 - 24.9 | Lowest risk |
| Overweight | 25.0 - 29.9 | Increased risk |
| Obesity Class I | 30.0 - 34.9 | High risk |
| Obesity Class II | 35.0 - 39.9 | Very high risk |
| Obesity Class III | 40.0 and above | Extremely high risk |
Calculate the healthy weight range for your height.
Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, overweight and obesity in adults. It is defined as the weight in kilograms divided by the square of the height in meters (kg/m²).
BMI provides the most useful population-level measure of overweight and obesity as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness in different individuals.
For children and adolescents, BMI interpretation is age and sex-specific. The calculator on this page is designed for adults 20 years and older.
The formula for BMI was devised in the 1830s by Belgian mathematician Adolphe Quetelet. It is calculated the same way for both adults and children. The calculation is based on the following formulas:
or
BMI = [weight (kg) ÷ height (cm) ÷ height (cm)] × 10,000or
BMI = weight (lbs) ÷ (height (in) × height (in)) × 703While BMI is a useful screening tool, it has limitations:
BMI does not differentiate between muscle and fat. Athletes and bodybuilders with high muscle mass may have a high BMI but not be overweight or obese.
BMI does not account for differences in body composition between men and women, or changes that occur with age.
Different ethnic groups may have different associations between BMI, percentage of body fat, and health risks.
BMI does not indicate where fat is located on the body. Abdominal fat carries higher health risks than fat distributed elsewhere.
For a more accurate assessment of health risks associated with weight, consider waist circumference and other factors in addition to BMI.
Being underweight may indicate malnutrition, osteoporosis, decreased immune function, fertility issues, and increased risk from certain diseases.
Individuals in this range generally have the lowest risk for weight-related health problems. However, other factors like diet, exercise, and genetics also play important roles.
Being overweight increases the risk of developing heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers.
Obesity significantly increases the risk of serious health conditions including heart disease, stroke, type 2 diabetes, certain cancers, sleep apnea, and osteoarthritis. The risk increases with higher BMI categories.