To determine the size of a sliding door you can follow these guidelines;
Width Measurement;
For a sliding glass door start at the point where the door frame meets the exterior of your home. Measure horizontally, from one side to another considering the distance between bricks, siding or stucco.
If you have doors measure their width horizontally since they are paired.
Height Measurement;
To measure the height of a sliding glass door begin from the bottom of the door sill. Measure vertically up to the top of the frame.
For doors measure from the floor, to each doors height.
Depth Measurement;
Measure the width of the jamb without including any trim. This will help determine how deep your door opening should be.
Recording and Verification;
Remember to record all measurements accurately and double-check them for precision before proceeding.