Measure the top diameter across the widest point
Measure the bottom diameter across the widest point
Measure the slant height from the top edge to the bottom edge
Measure the height from top to bottom
Measure the fitter size at the lamp base attachment point
Measure the inside diameter if the shade has a recessed top or bottom
Measure the widest width if the shade is oval or rectangular
Measure the depth if the shade is not round
Measure the harp height if needed for lamp compatibility
Record all measurements in inches or centimeters consistently