Roofing projects require accurate material estimates, as roofing materials are typically sold by the roofing square (100 square feet) and underestimating can cause costly delays while overestimating wastes money. This roofing calculator computes the roof area based on your building's dimensions and roof pitch (slope), then estimates the number of roofing squares needed along with an adjustable waste factor for cuts, overlaps, and ridge/valley areas. It's useful for homeowners planning a roof replacement, contractors quoting jobs, or DIYers tackling a roofing project who need a realistic materials estimate before purchasing shingles, tiles, or other roofing materials.