Roofing Square & Material Calculator
Calculate total roofing squares, bundles, and waste for your project.
Flat (0/12)
2/12
3/12
4/12 (Standard)
5/12
6/12
7/12
8/12
9/12
10/12
12/12
Total Surface Area
0 sq ft
Roofing Squares
0
Bundles Needed (3/sq)
0
Material incl. Waste
0
How to Calculate Roofing Squares
In the roofing industry, the term "Square" refers to a 100-square-foot area (10′ x 10′). Unlike standard flooring, roofing calculations must account for the slope or pitch of the roof, which increases the actual surface area compared to the flat footprint of the house.
Understanding the Math
To calculate your roofing needs accurately, we use the following formula:
- Base Area: Length × Width
- Pitch Multiplier: We calculate the square root of ((Pitch/12)² + 1). For example, a 4/12 pitch has a multiplier of approximately 1.054.
- Actual Area: Base Area × Pitch Multiplier
- Squares: Actual Area ÷ 100
Waste and Bundles
A standard 10% to 15% waste factor is added to account for hip/valley cuts and ridge caps. Most standard asphalt shingles are sold in bundles, where 3 bundles typically cover 1 roofing square (33.3 sq ft per bundle).
Example Calculation
If you have a ranch-style home measuring 40ft by 30ft with a standard 4/12 pitch:
- Footprint = 1,200 sq ft.
- Adjusted for 4/12 pitch (x 1.054) = 1,265 sq ft.
- Add 15% waste = 1,455 sq ft.
- Total = 14.55 Squares (or 44 bundles).