Free BMI Calculator: Check Your Body Mass Index

Our Body Mass Index (BMI) calculator provides a reliable measure of body fat based on your height and weight. It's a widely used tool to help you understand if you are in a healthy weight range. This calculator is suitable for adults, teens, and children, and uses up-to-date classifications from the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC).

How to Use the BMI Calculator

Getting your BMI result is simple:

1. Select Your Units: Choose between Metric (kg, cm) or US/Imperial (lbs, ft, in) units.
2. Enter Your Details: Provide your current age, gender, height, and weight.
3. Click "Calculate BMI": Instantly see your BMI score, your weight category, and a visual representation on our BMI gauge.

What is BMI?

Body Mass Index (BMI) is a numerical value of your weight in relation to your height. It is a simple and inexpensive screening method for weight categories that may lead to health problems. The formula used for adults is universal, but the interpretation of the result changes for children and teens.

Understanding Your BMI Results

For Adults (Age 20 and over)

For adults, BMI is interpreted using standard weight status categories that are the same for all ages and for both men and women. These are based on the World Health Organization (WHO) recommendations.

For Children and Teens (Age 2-19)

For children and teens, BMI is interpreted differently. It is age-and-sex-specific and is often referred to as BMI-for-age. After calculating the BMI value, it is plotted on a CDC growth chart to determine the corresponding percentile. Because this requires complex percentile charts, our calculator provides the BMI number and advises consulting a healthcare provider to determine the official percentile.

Limitations of BMI

While BMI is a useful indicator of body fatness for most people, it does have limitations. It does not directly measure body fat and does not account for factors like muscle mass, bone density, and body composition. For example, a very muscular athlete may have a high BMI that classifies them as "overweight" even with very low body fat. Therefore, BMI should be used as a screening tool, not a diagnostic one.

Disclaimer: This calculator is for informational purposes only and is not a substitute for professional medical advice. Consult with a doctor or other qualified healthcare provider with any questions you may have regarding a medical condition.