Orthopedic pillow height (loft) depends on shoulder width and sleep position. For side sleepers, it should fill the gap between shoulder and head so the head does not drop—often meaning a higher loft. For back sleepers, the goal is a lower loft that supports the neck gap without pushing the chin toward the chest. A practical check: on your side, your nose–chin–sternum should stay in one line; on your back, your gaze should point upward without excessive backward tilt. A single “cm” standard is unreliable because mattress firmness and body proportions change the outcome. Adjustable fill designs can be especially useful for dialing in the right height.