One important reason to measure body fat is because it is different to body weight. Losing body weight does not necessarily mean that you have lost body fat because it measures everything that constitutes the human body and not just the fat. Someone who looks relatively trim may in fact have high levels of body fat. So it is important to lose body fat as part of your weight loss plan.

Body fat is measured in percentage terms using various techniques. Some of the common techniques of measuring body fat level include body fat scales, hydrodensitometry, and skinfold calipers measurement. These have been explained below:

Body fat scales: In this method, a low current is passed through your body. The resistance offered to the passage of this current depends on your body fat level.

Hydrodensitometry weighing: Also known as underwater weighing or hydrostatic weighing, this method measures your body fat level by your body volume and body weight in water. Your weight is first measured outside water and then you are immersed in a pool of water. Your weight is measured under water. Your weight in water depends on the amount of fat in your body. The more the fat content of your body, the lesser your weight under water. Your body volume is measured and a formula is used to measure you body fat level.

Skinfold calipers: The skinfold calipers measurement is also kown as Anthropometry. In this method, pressure is applied on your skin and the underlying tissue using calipers. Measurements are taken at various locations on the body and a mathematical formula is used to find your body fat level.

There are also less scientific, but some would say plausible way, to measure body fat. By seeing how your clothes fit every week or two. If the clothes that normally fit perfectly are slightly loose fitted after a week or two then it's a sign that you have lost some weight and possibly body fat. However, this is not an accurate measure of fat loss because it could be weight loss.