How does a skinfold caliper compare to a paper tape measure for estimating body fat? These two devices use very different methods. A caliper pinches a fold of skin at four body sites and calculates a percentage from the thickness. A paper tape measures body circumference at three sites and converts the numbers using a formula. You measure five boys and five girls with both devices. The caliper reads skin thickness on the bicep, tricep, back, and hip. The tape measures circumference on the abdomen, thigh or upper arm, and forearm. Each method produces a body fat percentage through its own formula. Compare the two results side by side to see which device gives a more consistent reading across all ten subjects.