Shingle Calculator
Roof area from footprint × pitch factor, then squares and bundles. Click any i for detail.
Roof
Building footprint (sq ft)
i
Footprint
Plan area under the roof, not including overhangs unless you add them here. |
|
|---|---|
Pitch (in 12)
i
Pitch
Rise per 12 run. A 6-in-12 is a common mid slope. |
|
Waste (%)
i
Waste
Hips, valleys, starter, and ridge. 10–15% is common; complex roofs need more. |
How to use this calculator
- Enter the plan footprint.
- Set roof pitch.
- Add waste for hips and valleys.
- Read squares and ~3 bundles per square.
Results explained
Roof area = footprint × √(1 + (pitch/12)²). Squares = roof area / 100 × (1 + waste%). Bundles ≈ squares × 3. Dollar reroofs use the roof cost calculator.
Quick reference: shingles
One square = 100 sq ft of roof area.
| Item | Detail |
|---|---|
| 6-in-12 factor | ≈ 1.118 |
| 3-tab / many laminates | 3 bundles / square |
| Starter + hip/ridge | Often in waste % or extra bundles |
| Pitch calculator | Rise/run → X-in-12 |
Ice-and-water shield is sold by the roll, not by the square.
How the estimate is built
roof = footprint × √(1+(p/12)²). squares = roof/100 × (1+waste%). bundles ≈ 3 × squares.
Example scenario
1,800 sq ft footprint at 6-in-12 with 10% waste → about 22 squares (~66 bundles).
FAQ
Roof cost vs this?
Cost calculator = labor + materials dollars. This page = squares/bundles.
Overhangs?
Add them to footprint or waste.
Metal roof?
Coverage is still squares; panel width is different.