Estimate roof area, squares, and shingles for a gable roof
This roofing calculator estimates the surface area of a gable roof, the number of roofing squares (1 square = 100 sq ft), and the number of shingle bundles needed (3 bundles per square). It also calculates the estimated material cost based on your cost per square.
Enter the building length and width, roof pitch (rise per 12 inches of run), and overhang to get started.
Standard 3-tab shingles come with 3 bundles per square (100 sq ft). Architectural shingles may also require 3–4 bundles per square. Always add 10–15% for waste, especially on complex roofs with valleys and hips.
A roofing square is a unit of measure equal to 100 square feet of roof surface. Roofing materials are typically priced and sold by the square, making it the standard measurement for estimating material quantities and labor costs.