Patio doors are often measured for single-panel curtains. Single-panel curtains move only one direction on the rod, stacking at the opposite end. Patio door curtains will move away from the side of the door that opens, gathering over the stationary side of the door. When measuring your patio doors, make sure you allow for privacy and your curtain hardware.
Measure the outside width of your patio door. Add 4 inches to each side of your door for privacy. Your patio curtain measurement includes the actual door measurement plus 8 inches.
Measure the distance from the floor to the outside height of your patio door. Add 4 inches to the overall measurement for the curtain hardware.
Measure the distance from the wall to your curtain rod. This measurement represents the return distance. The return is how far the curtains will hang from the wall.