Measuring the door frame
If frames are required measure the width of the structural opening and deduct 12mm for fitting tolerance. To give the overall width of the frame. Please note, frames are not included in the price of the door, they have to be ordered separately as many walls are different widths.
Overall HEIGHT
Generally, the frame rests on the subfloor so measure from the head to the subfloor and deduct 10mm for fitting tolerance to give overall height of frame. In stud walls finer fitting tolerances can be workable check with your builder