MyYardCalcHow to use this roofing calculator
This model expands a rectangular footprint by equal overhangs and a single pitch factor. Roofs with dormers or mixed pitches should be broken into measured planes.
Use the manufacturer’s coverage per bundle. Ridge caps, starter courses, underlayment and flashings are additional items.
Roof surface = rectangular plan including overhang × √(1 + (pitch ÷ 12)²). One roofing square = 100 sq ft.
A worked example
With the example values shown below, the calculated result is 41 bundles. These are demonstration inputs, not installation specifications.
View the example measurements
- Building length: 40 ft
- Building width: 24 ft
- Overhang on each edge: 1 ft
- Roof pitch: 6 rise / 12
- Coverage per bundle: 33.3333 sq ft
- Extra allowance: 10 %
From estimate to order
Whole packages and pieces round up; measured lengths, areas and volumes keep full precision during calculation. Match the product dimensions and units to your quote, and check cuts, minimum orders and delivery before purchasing.