Measuring the windshield...

Firstly make sure all of your measurements are inside not outside! Begin as follows:

F - This is the vertical height of the windshield.
G - This is the sides of the windshield at the base.
H - This is the spread of the windshield in the back.
I - This is the length of the windshield at the top.
J - This is the top length of the side.
K -This is the length of the windshield at the base in the front.