is it safe to assume that a 40-fabric jelly roll (2 1/2") equates to approx. 2 1/2 yds of fabric? Am trying to figure out how many I would need for a king size, log cabin quilt - and my brain isn't functioning :P

It's just over 2.75 yards.

40 x 2.5" = 100"/36" = 2.77yds

thank you - my brain was too far off :lol:

It is about 2 3/4 yds.

But remember that with 2 1/2" strips, the seams will eat up a fair amount, for instance if you just sewed them together, each finished strip would be 2", so
40 x 2" = 80"/36" = 2.2 yards.
You cut up straight yardage too, just something to keep in mind.

This is it. I couldn't find my calculator so I used the Excel spreadsheet to do the math.

ali