Roofing Calculator
Estimate how many squares of shingles your roof needs, plus underlayment, ridge cap, and nails. Enter your roof footprint dimensions, pitch, and waste factor for an accurate material list that accounts for actual roof slope area.
Enter Roof Details
Full Breakdown
Footprint Area
Roof Pitch
Actual Roof Area
With Waste
Roofing Squares
Shingle Bundles
Underlayment Rolls
Ridge Cap
Roofing Nails
How to Use This Calculator
- Enter the length and width of the roof footprint (the building footprint).
- Enter the roof pitch as rise over run (e.g., 6:12 means 6 inches of rise per 12 inches of run).
- Set a waste factor (10% is typical for standard roofs, 15% for complex roofs).
- Click "Calculate Roofing" for a complete materials list.
The Formula
Pitch Multiplier = √(rise² + run²) ÷ run
Roof Area = Footprint × Pitch Multiplier
Squares = (Roof Area × (1 + Waste%)) ÷ 100
Roof Area = Footprint × Pitch Multiplier
Squares = (Roof Area × (1 + Waste%)) ÷ 100
One roofing square = 100 sq ft. Standard 3-tab shingles require 3 bundles per square. Underlayment rolls cover approximately 4 squares each. Ridge cap and nails are estimated proportionally.