Roof Area Calculator

Calculate Square Footage & Roofing Squares Instantly

Use the Roof Area Calculator to quickly determine your total roof surface area in square feet and in roofing squares (1 square = 100 sq ft). Just enter the building footprint length and width and your roof pitch, and the tool applies the correct slope multiplier to convert flat footprint area into actual sloped roof area. Accurate roof area is the foundation of every roofing estimate — shingles, underlayment, plywood, drip edge, ridge cap, and labor are all priced per square. Use the result here as the starting point for the rest of our calculators.