I had a series of electronic body composition measurements taken at a gym over a period of months. The practitioner used electrodes all over my body, with skin preparation as would be used for an EKG, and still the variation in readings was far greater than could be possible, thus invalid. As others have said, get calipers and learn how to use them.Also, people, forget about BMI. This was a measurement developed to study POPULATIONS, and never intended for the evaluation of individuals. Use common sense. How can a value that considers only weight and height be a valid reflection of an individual's health and fitness? Muscle is denser than fat, so an individual with minimal muscle will show a lower BMI than a heavily-muscled one of the same stature. Are we to believe that the lower BMI in this example indicates the healthier of the two? Nonsense!