Roof Replacement Cost Calculator
Estimate a simple roof replacement budget from footprint, pitch, waste, roofing materials, tear-off, installation labor and accessory allowances.
Default project preview
$18,047.69
Roof area
1,610 ft²
Material order area
1,803 ft²
Roofing materials
$6,491.39
Tear-off and disposal
$2,978.44
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Building length
Enter this project assumption in ft. The current imperial default is 48 ft.
Building width
Enter this project assumption in ft. The current imperial default is 30 ft.
Roof rise
Enter this project assumption in in per 12. The current imperial default is 6 in per 12. Minimum: 0.
Waste allowance
Enter this project assumption in %. The current imperial default is 12 %. Minimum: 0. Maximum: 35.
Roofing material rate
Enter this project assumption in per ft². The current imperial default is 3.6 per ft². Minimum: 0.
Tear-off and disposal rate
Enter this project assumption in per ft². The current imperial default is 1.85 per ft². Minimum: 0.
Installation labor rate
Enter this project assumption in per ft². The current imperial default is 3.75 per ft². Minimum: 0.
Underlayment and flashing allowance
Enter this project assumption in per ft². The current imperial default is 1.05 per ft². Minimum: 0.
Permit, delivery and setup allowance
Enter this project assumption in fixed. The current imperial default is 850 fixed. Minimum: 0.
How to read the outputs
Roof area
simple equal-slope roof model. Default preview: 1,610 ft².
Material order area
includes waste. Default preview: 1,803 ft².
Roofing materials
entered order-area rate. Default preview: $6,491.39.
Tear-off and disposal
existing roof removal. Default preview: $2,978.44.
Labor and accessories
installation, underlayment and flashing. Default preview: $7,727.85.
Cost per roof area
per ft². Default preview: $11.21.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Roof area = footprint area × √(1 + slope ratio²). Material area adds waste. Total cost adds materials, tear-off, labor, accessories and fixed allowances.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: July 29, 2026
Use this calculator to build a preliminary roof-replacement budget from measured roof area, pitch-adjusted waste, tear-off, underlayment, accessories, labor and disposal. It does not replace a site inspection or contractor proposal.
Calculation steps
- 1Measure actual roof planes or use a verified roof-area estimate.
- 2Apply pattern and complexity allowance.
- 3Enter material, tear-off, labor and accessory rates consistently per square or area.
- 4Add permits, disposal and contingency without double counting.
Worked numerical example
A 2,400 ft² measured roof with 12% waste becomes 26.88 roofing squares. At entered material, labor and disposal rates, the calculator totals the scenario and shows the cost per square separately.
Purchasing and rounding
Shingles, underlayment, starter, ridge cap, flashing and ventilation are separate products. Round each to its own package coverage rather than treating one cost rate as a complete material list.
Interpret the result
The total is a comparison scenario. Steepness, access, decking damage, flashing details and regional labor can move real bids substantially.
Page-specific assumptions
- Roof area is accurate.
- Rate units are consistent.
- Deck repairs are included only if entered.
- No concealed-condition allowance beyond the stated contingency.
Common mistakes
- Using building footprint without pitch adjustment.
- Treating waste as profit or contingency.
- Omitting tear-off and disposal.
- Comparing bids with different accessory scope.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Roof Replacement Cost Calculator questions
Does footprint area equal roof area?+
Not on a sloped roof. The calculator applies a slope factor to estimate the surface area.
Are sheathing repairs included?+
Only when the fixed or accessory allowance includes them. Unknown deck damage is commonly priced separately.
Why use a waste allowance?+
Starter strips, hips, ridges, valleys, cuts and damaged material make ordered coverage exceed measured roof area.