Flat (0/12)
Low (1/12)
Low (3/12)
Medium (5/12)
Medium (6/12)
High (8/12)
Steep (10/12)
Steep (12/12)
Base Footprint:0
Actual Surface Area:0
Total Squares (incl. waste):0
Estimated Total Cost:$0.00
How to Estimate Your Roofing Project
Calculating the cost of a new roof requires understanding "Roofing Squares." In the roofing industry, one square is equal to 100 square feet of roof surface. This calculator helps you convert your home's footprint into actual roofing squares by accounting for the pitch (slope) of your roof and the necessary waste factor for cuts and overlaps.
Understanding Roof Pitch and Multipliers
Because roofs are slanted, the surface area is always larger than the flat footprint of the house. The steeper the pitch, the more material is required. Our calculator uses the following pitch multipliers:
Low Pitch (3/12): Multiplier of 1.03
Medium Pitch (6/12): Multiplier of 1.12
Steep Pitch (12/12): Multiplier of 1.41
The Importance of Waste Factor
No roofing project is perfectly efficient. You must account for shingles that are cut at valleys, hips, and gables. A standard gable roof typically requires a 10% waste factor, while complex roofs with many dormers and valleys may require 15% to 20%.
Example Calculation
If you have a home that is 40 feet long and 30 feet wide:
Base Area: 40 x 30 = 1,200 sq. ft.
Adjust for Pitch: For a 6/12 pitch (1.12 multiplier), 1,200 x 1.12 = 1,344 sq. ft.
Add Waste: 1,344 + 10% = 1,478.4 sq. ft.
Convert to Squares: 1,478.4 / 100 = 14.78 Squares.
Total Cost: If the price is $400 per square, your total is roughly $5,912.