Panel coverage and overlap
Metal roof panels have an overall width and a smaller coverage width that accounts for the side lap. The number of panels across a roof plane equals the eave length divided by the coverage width, rounded up. Panel length is typically the full slope length from eave to ridge.
Standing seam panels interlock without exposed fasteners, while corrugated and R-panel profiles use exposed screws at each rib.
Panels = ceil(Eave length / Coverage width)
Round up to ensure full coverage across the roof plane.