Exterior
Roofing Calculator
Estimate asphalt shingle bundles by roof area, pitch factor, and waste.
Inputs
4/12=1.06, 6/12=1.12, 8/12=1.20
Live estimate
Bundles needed
51
- Actual roof area
- 1,680 sq ft
- With waste
- 1,680 sq ft
- Roofing squares
- 16.8
Live estimate
- Mathematical quantity
- 51
- Material behavior
- Not applicable
- Field conditions
- Not applied
- Ordering rule
- Round up to whole bundle
- Suggested order
- 51
Estimator confidence
HighStraightforward geometry with well-defined material.
- Pitch factor — Steep roofs pack more area under the same footprint.
- Waste for hips, valleys, and starter — Complex roofs waste more shingles per bundle.
- Confirm actual roof pitch — steeper pitches change bundle counts significantly.
- Order starter, field, and cap shingles as separate line items.
- Underlayment and ice-and-water shield are separate materials — don't forget them.
- Calculating from the plan area instead of the pitched roof area.
- Forgetting starter and cap shingle counts.
- Skipping ice-and-water shield in cold climates.
Smart tips
- Ordering 5–10% extra is standard on irregular layouts. Running short costs more than the excess.
How it's calculated
Actual roof area = footprint × pitch factor.
With waste = actual × (1 + waste %).
Squares = area ÷ 100. Bundles = ceil(area ÷ bundle coverage).
Material assumptions
- Pitch factor: 4/12 = 1.06, 6/12 = 1.12, 8/12 = 1.20, 12/12 = 1.41.
- 3-tab shingle: 3 bundles per square (100 sq ft).
- Architectural: often 3 bundles per square as well, but heavier.
Frequently asked questions
Related calculators
Related articles
Deeper guidance from the Learn library — sizing, depth, waste, and ordering for this material.
Roofing quantity can vary significantly based on valleys, hips, penetrations, and waste. Get a measurement from your roofer.