Roofing calculator
Estimate roof area, roofing squares, shingle bundles, material range, tear-off, labor range, and a starter shopping list from footprint, measured sections, known area, or pitch inputs.
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
- standard pitch uses a 1.12x planning factor
- U.S. near average; pricing data: U.S. near average pricing
Planning estimate only. Not a contractor quote, engineering advice, or permit review.
Calculator setup
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
Take this estimate with you
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Shared links include the current inputs and unit setting. Saved estimates stay local unless you enable Google Drive sync.
Assumptions in this estimate
- Roofing square is 100 sq ft
- 10% waste buffer
- 3 bundles per square for planning
- standard pitch uses a 1.12x planning factor
- U.S. near average; pricing data: U.S. near average pricing
No saved estimates yet.
What this calculator estimates
This roofing calculator starts from the measurements and options you enter, then estimates material quantity, waste, cost ranges, labor ranges, and a starter shopping list.
Results adapt to the selected region and unit settings, so the estimate is not locked to one market or measurement system.
Report confusing results, missing options, or assumptions that look off.
How this is calculated
- Footprint mode starts with length x width, then applies pitch and complexity factors before waste.
- Roof sections mode adds measured roof-surface planes before waste.
- Known area mode starts from the measured roof surface area you enter.
- Pitch converter mode turns rise over 12 into a geometric pitch factor 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 2026-06-21 · high confidence |
| Bundles per square | 3 | 3 | 4 | Homewyse asphalt shingle roof cost calculator Checked 2026-06-21 · medium confidence |
| Installed roof range | 500 | 650 | 820 | Homewyse asphalt shingle roof installed benchmark Checked 2026-06-21 · 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.
When should you use roof sections mode?
Use roof sections mode when you have measured individual roof planes from plans, a satellite tool, or contractor notes.
Does this replace measuring the roof?
No. It is a planning estimate. A roof should be measured directly before ordering.
Does this include metal roofing?
No. This calculator is currently for asphalt shingle planning.
Can this roofing calculator estimate cost by region?
Yes. The calculator uses the selected region and unit settings to adapt quantities, cost ranges, labor ranges, and assumptions.
How should you use the result before buying materials?
Use the result as a planning estimate, then compare it with a current supplier cart, contractor quote, or local project conditions before committing.
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.
Read the how much roofing do I need guide
Read the how many shingle bundles do I need guide
Read the what is a roofing square guide
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