BMI Calculator

Body Mass Index

About this BMI calculator:

Body Mass Index (BMI) is a numerical value derived from an individual’s weight and height, commonly used to categorize their weight status. It is calculated by dividing a person’s weight in kilograms by the square of their height in meters (kg/m²). A calculator is provided below however if you want to do the math yourself the formula is:

Weight (kg)Height (m)2

Alternatively, for those using pounds and inches, the formula is:

Weight (lbs)×703Height (in)2

BMI is used as a screening tool to identify possible weight problems in adults, although it is not diagnostic of the body fatness or the health of an individual. The World Health Organization (WHO) categorizes the ranges as follows:

  • Underweight: BMI less than 18.5
  • Normal weight: BMI 18.5–24.9
  • Overweight: BMI 25–29.9
  • Obesity: BMI 30 or greater

These categories help in assessing the risk of developing health problems associated with being underweight, overweight, or obese. For instance, a high BMI is linked to an increased risk of heart disease, diabetes, and certain cancers, while a low BMI might indicate malnutrition, osteoporosis, or other health issues.

However, this has limitations. It does not differentiate between muscle and fat mass, meaning that athletes or individuals with high muscle mass might be classified as overweight or obese when they are actually healthy. Similarly, it might not accurately reflect the health status of older adults who have lost muscle mass. Other measures, such as waist-to-hip ratio, body fat percentage, and overall fitness assessments, can provide additional insights into an individual’s health.

Despite these limitations, Body mass index remains a widely used and straightforward tool for initial health assessments and population studies, helping guide public health policies and personal health decisions.

BMI Calculator
Use this calculator to check your body mass index (BMI).
BMI Calculator
Unit type
Height
cm.
Please enter value between 125 and 225.
Weight
kg.
Please enter value between 10.0 and 500.0 ( one decimal ).
Height
ft.
in.
Please enter value between 4.2 and 7.3
Weight
lb.
st.
Please enter value between 22.0 and 1000.0 ( one decimal ).
Calculate BMI
Use this calculator to check your body mass index (BMI), which can be a helpful tool in determining your weight category. Or, use it to calculate your child’s BMI.