Fat Quarter Bundles
Fat Quarters are a quilter's best fabric friend. They measure 18" high x 22" wide, were the first specialty cut on the market, and are still the most common.
What makes it 'fat'?
A traditional quarter yard of fabric is cut from selvedge to selvedge (bolt end to bolt end), which gives you a piece measuring approximately 9" high x 44" wide, depending on the width of fabric you are working with. The majority of quilting-weight fabrics are 44-45" wide. This long and narrow traditional cut isn't very flexible in terms of the shapes you can cut from it.
The 18" x 22" Fat Quarter gives you a squarer shape with the same amount of fabric, but in a much better format from which to cut smaller squares, rectangles and/or triangles. It is actually a full quarter of a single yard of fabric (36" x 44"). If you divide a 36" x 44" piece into four equal pieces, each one will be 18" x 22".
Nearly all fabric manufacturers offer Fat Quarter bundles of one form or another, and that is exactly what they are called, however, Northcott Fabrics refers to theirs as Stone Rolls. Most Fat Quarter Bundles contain one Fat Quarter of every print in a collection, but because the number of prints in a collection varies widely, so do the number of Fat Quarters in any given bundle. Depending on whether or not the manufacturer includes the selvedge, your cut might end up at 18" x 21".