Asphalt
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Tons of hot-mix asphalt from your area and depth.
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Construction — Roofing
Roofing Calculator
Enter your roof footprint and pitch to get the true roof area, roofing squares and shingle bundles needed.
Roofing squares
—
1 square = 100 sq ft of roof.
| Roof area with pitch | — |
|---|---|
| Bundles 3 per square | — |
| Pitch multiplier | — |
Show our math
Enter your figures above to see the step-by-step working.
An estimate — complex roofs with hips and valleys need moreEverything computed client-side — nothing leaves this page
How the Roofing Calculator Works
A roof is bigger than the floor it covers because it slopes. The calculator takes your building’s footprint and multiplies it by a pitch factor — the square root of one plus the slope squared — to get the true roof area, then converts to roofing “squares” of 100 square feet each. Shingles are sold roughly three bundles to the square.
Enter the pitch as rise over run (for example 6 means the roof rises 6 inches for every 12 inches across). A steeper pitch means more surface area and more material. The waste allowance covers starter courses, ridge caps and offcuts.
roof area = footprint × √(1 + (pitch ÷ 12)²)
Frequently Asked Questions
What is a roofing square?
A square is 100 square feet of roof surface — the standard unit for ordering shingles. Asphalt shingles typically come three bundles to a square.
How does roof pitch change the amount?
A steeper roof has more surface area than its footprint. The calculator multiplies the footprint by a pitch factor, so a 6/12 roof is about 1.12 times its footprint, and a 12/12 roof about 1.41 times.
Is this for one roof plane or the whole roof?
Enter the total footprint the roof covers. For a simple gable roof the calculation captures both sloping sides. Complex roofs with hips, valleys and dormers need more waste — raise the allowance.
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