Roof area, roofing squares and shingle bundles from your footprint and pitch - waste factor included.
Bundles use 3 per square and include your waste factor, rounded up.
Actual roof area = footprint area × a pitch multiplier that accounts for the slope. A flat 0/12 roof has a multiplier of 1.0; a steep 12/12 roof is about 1.414. We divide the sloped area by 100 ft² to get roofing squares, the unit roofers order in. Shingles come 3 bundles per square, so bundles = squares × 3 × (1 + waste), rounded up.
Need to double-check a single plane or a flat area first? Run the numbers through our square footage calculator, then come back here to convert to squares and bundles. You can find every tool on the calculator hub.
Shingles, underlayment, nails and flashing delivered to your job site.
A roofing square is 100 ft² of roof surface. Multiply your footprint by the pitch multiplier for actual roof area, then divide by 100.
Standard 3-tab and most architectural shingles run 3 bundles per square. Heavier designer shingles can be 4–5 - check the wrapper.
Measure the footprint length and width on the ground, then apply a pitch multiplier. For hips and valleys, measure each plane and add them up.
Plan 10% for a simple gable and up to 15% for cut-up roofs with hips, valleys and penetrations.
Pitch is rise over 12 inches of run. A 6/12 rises 6″ per foot, giving a slope multiplier of about 1.118.