Originally Posted by Holice
The cut width depends on the width of your seam. for a folded binding start with 6 times the width of your seam and adjust accordingly. However that formulae doesn't take into donsideration the folds of the binding both when you fold it initially and the fold to the back. Since most of my quilts have a 3/8" seam allowance I cut 2.5".
I agree that the width should be determined by the size finished binding you want. Like Holice, I start with my finished width but then I multiply by 7 for a handstitched seam. Since I don't do handstitching very much but do almost all bindings totally by machine, I multiply my finished binding width by 7 then add 3/8th to give me enough extra to do that machine stitching.
As Holice and others have said, practice different ways and decide what works best for you.