2 1/4, 2 1/5 or 3". Depends on the size of the quilt.

I cut mine at 2 1/4" wide fold in half & press.

2-1/2

Most of the time I cut it 2 1/2 inches fold in half and press .

I used to cut them 2 1/2" because that's what I was taught to do, but there was too much overhang on the back side, so I cut it 2 1/4" now.

On most of my quilts I prefer a 5/16 inch finished binding, and cut them at 2.5 inches.

I make mostly charity quilts and use fluffy poly batting. I use 3.5" piece of fabric which makes kind of a wide binding. I also sew the charity quilts ones on by machine.

When I first started quilting it was 2 1/2 to 3, now it's
2 1/4".

I use a flat two inches for double fold binding. I like a very narrow binding, though. I've tried 1 3/4" but that is just a little too narrow to be workable.

I cut 2 1/2" and fold over to make it double. Machine stitch onto the top side of the quilt with 1/4" seam. Turn under, and slip stitch by hand on the back. I also miter the corners.