Measure the width of the door opening at the top, middle, and bottom
Measure the height of the door opening on the left and right sides
Use the smallest width measurement
Use the smallest height measurement
Measure the door jamb or frame depth if required by the screen door type
Check for any obstructions such as handles, trim, or thresholds
Measure from the outside edge of the frame if the screen door mounts there
Record all measurements in inches or millimeters
Verify whether the screen door is for an inswing or outswing door
Confirm the hinge side and handle side before ordering
Compare your measurements with the manufacturer’s sizing guide