Measuring by the shape of a window

Is rather easy to do, if you can read a tape ruler we accept measurements to the 1/8". Try to be as accurate as possible, measure only the pane of glass and not the frame work. We leave an extra 1/4" to 3/8" material border. The extra border helps in two ways: first it gives you a cushion if you didn't measure quite right. Second the image itself will not be damaged if banged around in shipping.