Body Mass Index (BMI) is a measure of body fat based on height and weight. Arm circumference is a measurement of the circumference of the arm at its widest point. How to work out BMI from arm circumference is a method of estimating BMI using only arm circumference measurements.
This method is important because it can be used to estimate BMI in people who are unable to be weighed or measured for height, such as those who are bedridden or obese. It is also a convenient way to track changes in body composition over time.