BMI Calculator

This article was medically reviewed by Dr. Uğur Tosun

What is BMI?

Body Mass Index (BMI) is a widely used tool for categorizing individuals based on their weight in relation to their height. It is a simple calculation used to assess whether a person has a healthy body weight for their height.

Understanding BMI

Calculation: BMI is calculated by dividing a person’s weight in kilograms by the square of their height in meters. The formula is: BMI = weight (kg) / (height (m))^2.
Categories: BMI values are divided into several categories, which typically include:
Underweight: BMI less than 18.5
Normal weight: BMI 18.5–24.9
Overweight: BMI 25–29.9
Obesity: BMI 30 or more

BMI Calculator

BMI Calculator


  • Health Indicator: BMI is used as a screening tool to identify possible weight problems for adults. A higher BMI can be associated with increased risk of various health conditions such as heart disease, stroke, type 2 diabetes, and certain types of cancer.
  • Limitations: BMI does not directly measure body fat or account for age, sex, ethnicity, and muscle mass. For example, athletes with high muscle mass may have a high BMI but are not considered overweight or obese.


  • Clinical Tool: In clinical settings, BMI is used as a simple and quick method for health assessments. It is a part of the initial evaluation, monitoring, and health risk assessment in adults.
  • Public Health: BMI is widely used in public health as an indicator to monitor the obesity trends in populations.


  • Age and Gender: BMI ranges can vary for children and teenagers; their BMI is age and gender-specific. For older adults, the normal range might be slightly higher.
  • Muscle vs. Fat: BMI does not distinguish between muscle and fat. Thus, the distribution of fat and muscle composition of the body is also important to consider.
  • Ethnicity: Different ethnic groups may have different associations with BMI and health risk. For instance, some populations are more prone to certain health conditions at a lower BMI.

BMI and Overall Health

  • Part of a Bigger Picture: BMI is one of many factors related to overall health. Other factors like diet, physical activity, waist circumference, and overall body composition also play a critical role.
  • Consult Healthcare Providers: It’s important to consult with healthcare providers for a comprehensive health assessment rather than relying solely on BMI.


BMI is a useful, but not definitive, tool for assessing body weight. While it provides a quick measure of weight-related health risk, it should be used in conjunction with other assessments for a more accurate health evaluation.

Remember, BMI is a general guide, and individual assessments can vary. For personalized advice, it’s always best to consult with healthcare professionals.