Roofing Square
roofing
A unit of roof area equal to 100 square feet — the unit shingles are sold and quoted in.
Roofers estimate, order, and bill in squares rather than square feet, so a 2,400 square foot roof is "24 squares" in every conversation you will have about it. Architectural shingles are packaged three bundles to the square; heavier designer profiles may take four. The figure that matters is the actual sloped roof area, not the building footprint — you must apply the pitch factor before dividing by 100.
Formula
Squares = (footprint ft² × pitch factor × (1 + waste)) ÷ 100
Example
A 1,200 ft² footprint at 6/12 pitch: 1,200 × 1.118 = 1,342 ft², plus 10% waste = 1,476 ft², ÷ 100 = 14.8 squares. Order 15.
Common mistake
Calculating squares from the building footprint without the pitch factor. On a 6/12 roof that understates the order by about 12%, which on a typical house is nearly two squares.
Use the Roofing Calculator
Calculate squares, shingle bundles, and underlayment for pitched roofs. Includes pitch correction for accurate area.
Open Roofing Calculator →Related Terms
- Roof Pitch — The slope of a roof expressed as inches of vertical rise per 12 inches of horizo…
- Waste Factor — The percentage added to a material estimate to cover cuts, breakage, and spillag…