Roofing calculator
Estimate roof area, roofing squares, shingle bundles, material range, tear-off, labor range, and a starter shopping list.
Home Project Estimates
Roofing calculator
May 9, 2026
40 ft by 28 ft footprint, standard pitch, moderate roof.
Shopping list
- architectural asphalt shingles45 bundles
- Underlayment, drip edge, flashing, starter, ridge cap15.0 squares
- Roofing nails and sealantAs needed
Assumptions
- Roofing square is 100 sq ft
- 10% waste buffer
- 3 bundles per square for planning
- U.S. near average; pricing data: U.S. near average pricing
Planning estimate only. Not a contractor quote, engineering advice, or permit review.
40 ft by 28 ft footprint, standard pitch, moderate roof.
Shopping list
- architectural asphalt shingles45 bundles
- Underlayment, drip edge, flashing, starter, ridge cap15.0 squares
- Roofing nails and sealantAs needed
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Assumptions in this estimate
- Roofing square is 100 sq ft
- 10% waste buffer
- 3 bundles per square for planning
- U.S. near average; pricing data: U.S. near average pricing
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How this is calculated
- Footprint area is length x width.
- Roof area applies pitch and complexity factors before waste.
- Roofing squares divide order area by 100 sq ft and shingle bundles use three bundles per square.
Assumption register
| Item | Low | Typical | High | Source |
|---|---|---|---|---|
| Roofing square | 100 | 100 | 100 | Homewyse asphalt shingle roof cost calculator Checked 2026-05-10 · high confidence |
| Bundles per square | 3 | 3 | 4 | Homewyse asphalt shingle roof cost calculator Checked 2026-05-10 · medium confidence |
| Installed roof range | 500 | 650 | 820 | Homewyse asphalt shingle roof installed benchmark Checked 2026-05-10 · low confidence |
Last reviewed: May 9, 2026. These values are planning defaults, not live prices.
Common mistakes
- Using house footprint as roof area without pitch and overhang allowance.
- Forgetting ridge cap, starter, underlayment, drip edge, flashing, and fasteners.
- Ignoring tear-off layers, decking repair, and safe roof access.
FAQ
What is a roofing square?
A roofing square is 100 sq ft of roof area.
Does this replace measuring the roof?
No. It is a planning estimate from footprint dimensions. A roof should be measured directly before ordering.
Does this include metal roofing?
No. This calculator is currently for asphalt shingle planning.
Limitations
This is not a roof inspection, fall-safety plan, or contractor quote. Pitch, dormers, valleys, tear-off layers, decking condition, and flashing details matter.
This estimate is for planning only. It is not a contractor quote, engineering advice, or permit review.
Next step
Measure once more, compare the result with a real quote or shopping cart, and review the assumptions before buying materials.
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