How do I Measure Body Mass & Body Mass Index?

Most Americans who struggle with weight control need measurements to track their progress. There are several ways of measuring body mass, with the body mass index being the simplest and most popular. The body mass index (BMI) is a measuring tool that rates your weight against the average, healthy weight of other people your height, weight and gender. When choosing a method to measure your body mass, decide how exact and precise the numbers need to be to suit your fitness needs, then choose the method accordingly.

Things You'll Need

• Digital skin fold caliper
• Scale

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Instructions

• 1

  Measure your body mass online by using the Centers for Disease Control and Prevention BMI calculator after weighing yourself on a scale. According to the CDC, a rating of 18.5 or lower means that you are underweight, a rating of 18.5 to 24.9 means that you are a healthy weight, and a BMW from 25.0 to 29.9 means that you are overweight. Anything above 30.0 is considered obese. The BMI has come under fire recently, with critics believing the boundaries are too restrictive and don't take into account those with high fitness levels whose weight is composed of muscle, like Olympians and body builders. Generally speaking however, the BMI is still the best tool for a quick assessment of body mass.

• 2

  Use a skin fold test to get a more precise measurement. While the BMI merely estimates a person's body fat, skin fold tests are considered much more accurate. Digital calipers are available online and at sporting goods stores. The measurements are taken at specific sites on the right side of the body. The tester pinches the skin fold and pulls it away from the underlying muscle so only the skin and fat tissue is being held. The caliper is then used to measure the skin fold thickness in millimeters.

• 3

  Get your body mass measured by a health professional. One of the most precise ways to calculate a person's body mass is to have a professional administer a hydrostatic weighing test at an approved facility, such as a university or a health research center. The subject sits on a seat and expels air from their lungs while being lowered into a stainless steel weighing tank. A hydrostatic test is expensive and time consuming, but it will give you the most accurate body mass assessment possible.