Roofing Calculator
Estimate your roof’s true surface area from its footprint and pitch, then convert it into roofing squares and shingle bundles needed for the job.
Roof Details
Result
Enter roof details to estimate materials
Disclaimer: This calculator provides a planning estimate only and is not a substitute for a professional roofing measurement. Complex roof shapes (hips, valleys, dormers) require additional material beyond this simple footprint-based estimate.
About the Roofing Calculator
Roofing materials are sold by the "square" — a roofing industry unit equal to 100 square feet of actual roof surface. Because a pitched roof has more surface area than its flat footprint, this calculator applies a pitch multiplier before converting to squares.
Understanding Pitch Multiplier
Roof pitch is expressed as rise over a 12-inch run (e.g. 6/12 means the roof rises 6 inches for every 12 inches of horizontal run). The steeper the pitch, the more actual surface area covers the same footprint — a 6/12 pitch adds about 11.8% more area than the flat footprint.
Shingle Bundles
Standard asphalt shingles are packaged so that 3 bundles cover 1 square (100 sq ft). This calculator rounds up to whole bundles to ensure you order enough.