Estimate roof area, roofing squares, bundles, and extra material for asphalt shingle, metal, and other roofing projects.
Base area formula:
Roof length × roof width = base roof area
Pitch factor:
√(run² + rise²) ÷ run
This calculator adjusts the flat area using roof pitch to estimate true roof surface area, then converts it into roofing squares and bundles.
Knowing how much roofing material you need helps when planning re-roofing and new construction projects so you can order enough material before work begins.
Extra roofing material is often useful for valleys, flashing areas, damaged shingles, and future repairs.
Your result shows the estimated roof surface area based on your roof dimensions and pitch. It also calculates roofing squares and bundle count using the selected bundles-per-square setting.
Actual roofing needs can vary depending on dormers, valleys, overhangs, hips, ridges, and waste during installation. Always compare the result with your final roof measurements and supplier recommendations.
Start with the roof's base length and width, then multiply by a pitch factor to estimate the actual sloped roof area.
One roofing square equals 100 square feet of roof area.
Many asphalt shingle products use 3 bundles per square, but some products need 4 or 5, depending on the shingle type.
Many projects use around 5% to 15% extra depending on roof complexity, cuts, and waste.