Free project planning tool
Estimate sloped roof area, roofing squares, full shingle bundles, waste, and material cost from roof dimensions and pitch.
Roof-system takeoff
Field shingles cover the main roof planes, but a complete roof order also depends on geometry, accessory coverage, existing conditions, and the selected manufacturer system.
Two main planes, one ridge, and few penetrations create a relatively repeatable layout.
A moderate waste allowance may be suitable, but starter and ridge products still require separate linear measurements.
Hips, valleys, short planes, and intersecting sections create more cuts and accessories.
Have the plane takeoff and accessory list checked by a roofer or supplier before ordering.
Existing roofing will be removed and the deck condition may not be known in advance.
Use a separate contingency for concealed repair; do not inflate the shingle waste percentage to cover it.
Read the result
Roof surface includes slope, overhangs, and every roof plane; it is rarely identical to living area.
Bundle coverage varies by product. Use the exact wrapper or technical data.
Keep field-shingle cuts, accessories, and concealed-condition contingency as separate quantities.
Complete workflows
This roofing calculator converts the horizontal roof footprint into sloped surface area using the roof pitch. It then adds your waste allowance and rounds the result up to full shingle bundles, producing a practical purchase quantity rather than a fractional estimate.
Use the bundle coverage and price printed by the manufacturer or supplier. Product coverage varies, so replacing the default values is the simplest way to improve the shingle quantity and cost estimate.
The estimate is designed for early material planning on a simple roof footprint. Complex roofs should be divided into measurable sections or checked by a roofing professional.
Formula
A 40 × 24 ft roof footprint at a 22.6° pitch has roughly 1,040 sq ft of sloped area. With 12% waste and 32.3 sq ft per bundle, the estimate rounds up to 37 bundles.
Common questions
Calculate the sloped roof area, add a waste allowance, and divide by the coverage printed on one bundle. Always round up to complete bundles. This calculator performs those steps using your roof dimensions and pitch.
Multiply the required full bundle count by the price per bundle. The result is a shingle material estimate only; underlayment, flashing, ridge caps, starter strips, fasteners, labor, and disposal may be separate.
In US roofing, one roofing square equals 100 square feet of roof surface. It is a measurement of area, not a square-shaped bundle.
Yes. A sloped roof has more surface area than its flat plan footprint. The calculator uses the pitch angle to account for that increase.
Simple gable roofs may use about 10%. Roofs with hips, valleys, dormers, or intricate cuts often require a higher allowance.
Planning guides