I always make my bias binding using this tutorial
http://piraterodgers.com/tutorials/cbt/index.htm as mentioned by Cari. This one is easy and makes sense. I had tried so many before finding this gem. I love stripy bindings and usually use a piece of fabric 28.5" long as this measurement makes well over 400" of 2.5" binding which is enough for any King sized quilt. To know how much fabric you will need for binding, figure on one 2.5" WOF strip yielding approximately 40" of binding. A 25.5" length of fabric would give you about 400" of binding.