fat quarter conversion?
 

I have a pattern that calls for:

• 1 x 2 1/2" fabric strip roll
• 42 x 5" charm squares

How many fat quarters would I need for this? Is there a way to figure it out?

Check out this QB post. It has a diagram showing you how to cut the FQ http://www.quiltingboard.com/main-f1...w-t140557.html

It is possible to cut 56 5" squares from one yard of fabric, so there are your first four fat quarters. (3 FQ's will only yield 40 5" squares, so not enough).

There are 1512 square inches per yard. The yardage of a jelly roll is 40" x 2.5" x number of strips (I am unaware of how many strips are in a roll). This number will then need to be divided by 1512 for yardage, then multiplied by four for FQs.

Strange that the pattern calls for a "fabric strip roll" rather than a jelly roll. A jelly roll contains 40 strips, but not all fabric strip rolls contain that many. There are several problems with figuring out how many FQs you need, one being that not all FQs are created equally. They should be 18" in one dimension, but the other dimension could be anything from 19" to 22". (Of course that applies to the jelly roll strips as well.) You can get 7 half-strips from each FQ. Assuming that your fabric strip roll is supposed to be 40 strips, that means you need 80 half-strips (maybe more, depending on how the strips are eventually supposed to be cut), so that means 12 FQs for the strips. Assuming a 19x18" FQ, you can only get 9 charm squares; but assuming that the FQ is 22x18 you could get 12 squares. See the waste in doing it this way? Anyway, if you assume that the FQ will produce 12 squares, you will need 4 of them for the charm squares. So the bottom line is at least 4 FQs for charm squares and 12 fabrics for strips. However - and this might be a big problem - this would mean you only have 4 fabrics in the 5" squares in your quilt instead of the variety of fabrics that is normally in a charm pack, and only 12 fabrics in the strips instead of the 40 in a jelly roll. I don't normally buy pre-cuts, but in this case I would look at Connecting Threads because their pre-cuts are very reasonably priced.

Tell us what pattern you are using and what size blocks or squares or rectangles you need.

Someone mentioned on the other posted link that if you needed to cut three 12 1/2" pieces from one strip you would need more strips cut - like three strips just to get three pieces.

I agree.. but it may be a licensing issue. I'm pretty sure that "Jelly Roll" belongs to Moda.

Many of my recent FQ's have been measuring under 18 inches wide and more like 17 so you can't even count on that anymore. I was cutting my most recent project from FQ's and was cutting them into 2.5 inch strips. If they were at least 17.5 inches wide I could get 7 strips but there were several pieces that I could only get 6 strips. It left me short.