jelly rolls are 2 1/2" strips by width of fabric....how many strips vary - sometimes only 20 strips, sometimes 40...you have to check the individual one you are looking at to know how many strips there are. 20 strips give you 50" of fabric x width (usually 40-42") layer cakes are 10" squares--again, depends on how many fabrics are in the collection- varies - description should tell you how many- I've seen them with as few 23 and as many as 54...you can get 12 (3 = 30" out of 36" ; x 4 = 40" width of fabric) in a yard of fabric- so if the stack has 24 squares you are getting about 60" x 40" charm squares are 5" squares. (7 x 8 = 56 in a yard) 7= 35"; 8= 40"; sometimes charm squares will have 2 of each fabric - or 4 of each fabric instead of them all being different...and again- how many charms are in the pack vary from pack to pack.