Roofing Calculator
Calculate roofing materials and shingles needed
Enter Roof Dimensions
Common pitches: 4 (low), 6 (moderate), 8 (steep)
Typically 10-15% for shingles
Roofing Estimate
About This Calculator
The Roofing Calculator helps you estimate the amount of roofing materials needed for your project. It calculates the roof area accounting for pitch, adds waste factor, and estimates the number of shingle bundles and squares required.
This tool is essential for homeowners, contractors, and DIY enthusiasts planning roofing projects. The calculator accounts for roof pitch (slope) and includes a waste factor to ensure you order enough materials for your project.
Formula & Calculation Method
Roofing calculations use the following formulas:
- Pitch Multiplier: √(1 + (Pitch/12)²)
- Roof Area: Base Area × Pitch Multiplier
- Total Area (with waste): Roof Area × (1 + Waste%)
- Squares: Total Area / 100 (1 square = 100 sq ft)
- Bundles: Squares × 3 (typical shingle coverage)
Where:
- Pitch is measured in inches per foot (e.g., 6" = 6 inches rise per 12 inches run)
- Base Area = Length × Width
- Waste factor accounts for cuts, overlaps, and mistakes (typically 10-15%)
How to Use This Calculator
Frequently Asked Questions
What is a roofing square?
A roofing square is a unit of measurement equal to 100 square feet. Roofing materials are often sold by the square, making it easier to estimate quantities needed for a project.
How do I measure roof pitch?
Roof pitch is measured as the vertical rise in inches per 12 inches of horizontal run. For example, a 6/12 pitch means the roof rises 6 inches for every 12 inches of horizontal distance.
Why is a waste factor needed?
A waste factor accounts for material lost due to cuts, overlaps, starter strips, ridge caps, and mistakes during installation. Typically 10-15% waste is recommended for shingle roofing.
How many bundles are in a square?
Most standard shingles require 3 bundles per square (100 sq ft). However, this can vary by shingle type and manufacturer, so always check the product specifications.
Calculator by
NumCalculators Editorial Team
Multi-disciplinary Expert Team