Some customers are unsure whether to measure from the outside or the inside. In fact, our custom sliding door curtains are reversible, so there’s no need to worry about getting the direction wrong. You can measure from the outside or check from the inside, and either way will work perfectly without any issues. in other words, if you don't want to magnetic screen door opening in the middle , you can  just tell me you want to side opening how many inches from the edge is done