The pile of a carpet is determined by the length and thickness of its fibers. To determine if your carpet is medium or high pile, you will need to measure the height of the fibers from the backing. If it measures between 0.25 inches and 0.75 inches, then it is considered medium pile; if it measures more than 0.75 inches, then it is considered high pile. When measuring, make sure to use a ruler that can accurately measure in small increments for an accurate measurement result.