Body Mass Index (BMI) Calculator
Calculate your BMI and understand its implications for your health.
*This calculator is primarily for **adults (age 20 and over)**. For children and teens, BMI interpretation requires growth charts and should be done with a healthcare professional.
Category:
Health Risk:
Understanding BMI
Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is $BMI = \frac{weight(kg)}{height(m)^2}$ for metric units. For imperial units, the formula is $BMI = \frac{weight(lbs)}{height(inches)^2} \times 703$.
BMI is a screening tool, not a diagnostic tool. It can indicate categories of weight that may lead to health problems, but it doesn't measure body fat directly or assess overall health.
BMI Categories (Adults)
| BMI | Weight Status | Associated Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Potential nutritional deficiencies, weakened immune system, osteoporosis. |
| 18.5 - 24.9 | Normal (Healthy Weight) | Generally lowest risk of weight-related diseases. |
| 25.0 - 29.9 | Overweight | Increased risk of heart disease, type 2 diabetes, certain cancers, high blood pressure. |
| 30.0 and Above | Obese | Significantly increased risk of heart disease, type 2 diabetes, stroke, sleep apnea, certain cancers, severe joint problems. |
Important Considerations
- Muscle Mass: Athletes and very muscular individuals may have a high BMI without being overweight because muscle weighs more than fat.
- Age and Gender: BMI interpretation can vary for different age groups and genders, though the standard categories above are widely used for adults.
- Ethnicity: Some ethnic groups may have different health risks at different BMI levels.
- Body Composition: BMI doesn't differentiate between fat and muscle. Waist circumference, body fat percentage, and overall lifestyle factors provide a more complete picture of health.
- Children and Teens: BMI for children and teens (ages 2-19) is plotted on age- and sex-specific growth charts, as their body fatness changes with age. This calculator primarily addresses adult BMI. For children, consult resources like the CDC's Child and Teen BMI information.
How This Tool Works
This BMI Calculator operates entirely client-side within your browser. No data is sent to a server, ensuring your privacy. It takes your entered weight and height, applies the standard BMI formula based on your chosen unit system, and then categorizes the result.