Prism99

It took my computer a long time to load this post! Maybe because of the diagram?

When you say you are starting out with 10" squares, do you mean they are already cut at 10"? And that these would comprise the large finished squares in your diagram? If so, then your finished large square size using 1/2" seams would be 9". In your diagram, every other 9" finished square is composed of 4 squares. The finished size of those smaller squares would need to be 4.5" in order to match the 9" finished squares, so the cut size of those smaller squares with 1/2" seams would be 5.5".

Assuming your diagram is the complete quilt, you will need 32 squares that are cut 10" and 128 squares that are cut 5.5" (this is 32x4). This is just for the top.

Assuming your fabric is 40" wide (typical), you would need about 80" of yardage for the large squares (assuming no cutting mistakes). This works out to about 2.25 yards of fabric -- which I would definitely round up to at least 2.5 yards to allow for straightening the edge periodically and maybe one cutting mistake.

However, you also need yardage for the small squares. You can get about 36 squares of 5.5" size out of a yard of fabric, but you need 128 squares. This means you need a minimum of about 3.5 yards for the smaller squares.

This comes to a total of 6 yards just for the top layer of the rag quilt, without a big margin for possible cutting errors, fussy cutting, or stash accumulation of leftovers.

You would need another 6 yards for the middle layer, and another 6 yards for the bottom layer.

Yikes! I didn't realize a 60" square rag quilt with 1/2" seams would require this much yardage! Hopefully someone will check my math to make sure I haven't made a mistake with these calculations.