When figure the materials needed for a project, you would need to take a measurement of the height and the length of the wall you intend to cover. Divide the height of the wall by the height of your panel (in most cases, 2’) and the length of the wall by the length of the panel (in most cases, 3.5’). Multiplying these numbers together will give the number of full panels need for the area. For trim and ledger, measure your linear footage and divide by 4. This will be the number pieces needed.