There are a lot of seams, so there's a lot of fabric used up in the seams. It's the same for any quilt with lots of pieces.
It's a very easy process to make one!

I have made several OBW quilts. There are so many variables it is really hard to say how much fabric you would need. It depends on the size of triangles you cut, the pattern repeat etc. If it was me I would probably buy enough fabric to make 2 sets. 12 repeats of the design. Unless the repeat is pretty short. The repeat on the last one I made was 18 inches. Then you can adjust your quilt size by adding borders. (does this make sense?) Good luck. I look forward to seeing it. I have one on my design wall right now. I just can't decide on my layout for it. I have changed it 4 times so far. I am usually not this indecisive.

Would love to see the one on your wall.

Your pattern repeat will have some bearing on yardage. You need six lengths of the repeat for hexagon and eight for octagon blocks. I have not made a queen size but would guess it would take at least two sets of repeats. There is little waste. There was black in my fabric. We used black to fill in rows that were not complete and added a black border. If possible you might check your local library for one of the books. One Block Wonder and One Block Wonder Encore are two. There are others. Happy planning.

I agree with meanmom. There are so many variables - length of repeat, the width you cut your strips ( the wider the strips, the fewer you'll be able to cut per width of fabric). It takes some math to figure out how much yardage you need. Decide what width strip to cut and twice that will be the width of your hexagons, minus seam allowances. How many hex's wide do you need, plus the width of any borders. I'd use a wider strip, myself for a quilt that size, so you'll want a larger print in the first place. Good Luck!

I've seen a couple queen size OBW's and they are always awesome!

I usually buy 8-10 yards, depending on what the repeat looks like in the fabric, and what I want to do with borders. I like to border and back mine in the original fabric, it gives a great frame of reference for the hexies.

What is an OBW, please?

OBW = One Block Wonder

I must have missed something in the instructions for the one I am going to do, the way the instructions are written, I would not have much waste....aren't OBW and some Kaliedoscopes cut the same way? What am I missing?

My OBW will be 8 sided (45 degree triangle cuts) so how would that work with your example above? I am a math dunce and need your help with this please?