Roofing Shingle Calculator
Roofing Shingle Calculator how many bundles of shingles pitched roof material estimate roofing squares neededTurn roof plan area into a shingle quantity
Enter the building's horizontal roof dimensions, pitch rise, waste percentage, and the product's bundles per square. The estimate adjusts plan area for slope, converts to 100-square-foot roofing squares, and rounds bundles up.
Plan dimensions and pitch
Plan length times plan width is the horizontal projected area covering both sides of a simple roof footprint. The pitch multiplier is the square root of rise squared plus 12 squared, divided by 12. A 0-in-12 flat plane has a multiplier of 1; steeper roofs have more surface area.
Squares and bundles
One roofing square represents 100 square feet of roof coverage. Products commonly package a square across several bundles, but the number is not universal. Use the bundle count printed for the exact shingle product instead of assuming the default applies.
Worked example
A 40-by-30-foot plan is 1,200 square feet. At a 6-in-12 pitch, the multiplier is about 1.118, producing roughly 1,341.64 square feet of sloped area. Ten percent waste makes 14.758 squares. At three bundles per square, round 44.275 up to 45 bundles.
When a simple rectangle is not enough
Measure dormers, intersecting wings, porches, and other roof planes separately, then add them. Valleys, hips, rakes, starter courses, ridge caps, flashing, and unusual cutting patterns can increase material beyond a broad waste percentage. Subtracting openings is often inappropriate because cutting waste may offset small openings.
Use safe measurements
Plans, drawings, or ground-based measurements are preferable when available. Roof access involves fall risk and should be handled with appropriate equipment and qualified practice. This page estimates surface material only; it does not assess decking, underlayment, ventilation, fastening, structure, or installation requirements.
Limitations and privacy
The model assumes one rectangular footprint at one uniform pitch. It does not account for overhangs unless included in entered dimensions, and it does not select products or verify manufacturer coverage. Calculations remain in the browser.
Roofing Shingle FAQ
What is a roofing square?
It is a coverage unit equal to 100 square feet, not a physical square-shaped package.
Should I always use 10 percent waste?
No. Complexity and product instructions determine a suitable allowance.
Does the result include ridge cap?
No. Price and measure ridge, starter, and accessory products separately.