Estimate how many 2.5\u2033 strips (and jelly rolls) a quilt top needs.
Rough estimate using 2.5\u2033\u00d742\u2033 strips; add extra for seams and design.
A jelly roll is a rolled bundle of strips that are two and a half inches wide and as long as the width of the fabric, commonly about 40 strips per roll. After sewing with quarter inch seams, each strip finishes at two inches wide. The calculator estimates how many strips you need to cover a quilt top and how many rolls that comes to.
The strips are usable for the whole length of a quilt in some patterns, but are often cut into shorter pieces for blocks, borders, and bindings. Since each strip is about 42 inches long, a quilt wider than that needs the strips to be joined or cut and sewn in sections.
Strip quilts are a quick way to make a top, since the strips are already cut and matched. Plan the order of the strips on a table so that the colors are well spread, and sew them together in groups before you join the groups.
Leave some strips for binding if you like, and buy extra if you want to choose the best colors. Press the seams in one direction or open, and check that the finished widths of the strips are consistent before you continue.