Shingle Roof Calculator
Estimate the number of shingle bundles, underlayment rolls, and total cost for your roof project. Input roof dimensions, pitch, and waste factor to get accurate material estimates.
Published by:
isCalculator Editorial Team
Was this calculator helpful?
How to use this tool?
How to Use the Shingle Roof Calculator
- Enter Roof Dimensions – Input the Length and Width of your roof in feet (imperial units). Use decimals if needed (e.g., 40.5).
- Select Roof Pitch – Choose the roof slope from the dropdown (e.g., 6/12 for medium). This adjusts the area calculation for steepness.
- Set Waste Factor – Default is 10% to account for cuts and errors. Adjust between 0–50% as needed.
- Enter Cost per Bundle – Input the price of one shingle bundle in dollars (e.g., 30.00).
- Click "Calculate" – The results show:
- Total Roof Area in square feet (adjusted for pitch).
- Squares Needed (1 square = 100 sq ft).
- Shingle Bundles (3 bundles per square, rounded up).
- Underlayment Rolls (1 roll per 4 squares).
- Total Material Cost (bundles × cost per bundle).
All inputs are in imperial units (feet, dollars). The pitch factor formula is: √(144 + rise²) / 12.
Previous Results
| Result | Inputs | Date |
|---|
Frequently Asked Questions
Length is the distance along the eaves, width is the distance from eave to ridge. If you can't access the roof, measure from the ground using the house dimensions and add overhangs.
Roof pitch is the rise over 12 inches of horizontal run. Steeper roofs require more materials due to increased surface area.
Standard waste factor is 10-15% to account for cuts, mistakes, and ridge caps. Complex roofs may need up to 20%.