If there are 40 strips in each, the 1600 inches you start with finishes at 40 x 80 or so. 4 jelly rolls would yield about 80 x 80, if you use the same number of "turns" as the original pattern.

Oops, the actual number are different than above. The original size is 48 x 64 using one jelly roll. If you use 4, you will start with 6400 inches. Sew once, and it is 4" x 3200", twice it's 8"x1600", three times 16" x 800"' four is 32"x 400", 5 is 64" x 200", 6 is 128"x100", less the seam allowances. the seam allowances will use about 12" from the width and. 4" from the length, so 116x96 or so. Sounds about right for a queen, stripes going side to side.

I did several quilt tops last year using this as a way of using up some of 2.5" strips in coordinated colors. They went together fast.

Do a search on this board for Super Fast Jelly Roll Quilt. If you have the time, read thru all 57 pages for a wealth of info!

A jelly roll strip 2-1/2 x 42 yields about 82 square inches. A queen quilt 100 x 100 needs 10000 square inches. 10000/84 equals a smidge over 119 strips. You'd need about 3 jelly rolls to make a queen size. Might be fun to make the center out of the small baby quilt 1600 and then log cabin the rest of the rolls around that, mitering all the corners.

Forget the math, I want to know if you plan to make it like the jelly roll race, sewing one LONG strip? That would be... well, it would be fun to watch. :)

40 strips make a 48 x 68, 55 strips makes 55 x 84, 69 strips makes 70 x 83, 82 strips makes 78 x 88, 96 strips makes 88 x 92

Missouri Star Quilt has a tutorial on u tube, maybe if you google it you can find it, I tried to copy and paste it for you but for some reason it didn't work

I had wondered about this also so, thank you, Frances, for asking the question and thank you to all those who contributed the math solutions!

To use four jelly rolls would be too much to handle. Make four tops from using one jelly roll each and then sew the four tops together. That is about the only way to do it with out a big tangled mess.