What is a fat quarter? A fat quarter (or a quarter of a yard) is simply a yard of fabric cut in half horizontally and again vertically. A fat quarter measures approx. 18" x 22" (45cm x 56cm). Two fat quarters uncut = half a yard - 18" x 44" (45cm in length x 113cm in width). Four fat quarters uncut = one full yard - 36" x 44" (91.5cm x 113cm) generally for quilting fabrics.