Roofing Calculator
Estimate roof area, squares, and bundles.
Roofing bundles
37bundles
- Roof area with waste
- 1,229.8 sq ft
- Roofing squares
- 12.3
- Assumption
- Simple two-plane roof; excludes overhangs, valleys, dormers, and accessories
This is a planning estimate based on your inputs and assumptions, not an exact contractor, installer, or supplier quote.
What this calculator does
Estimate a simple pitched roof from building dimensions, pitch, waste, and bundle coverage.
Inputs and what they mean
- Dimension unit
- — choice value.
- Building length
- — number value.
- Building width
- — number value.
- Roof pitch rise per 12
- — number value.
- Waste allowance
- — number value.
- Coverage per bundle
- — number value.
How to use it
- Enter the project dimensions and choose their unit.
- Adjust waste, coverage, quantity, and other assumptions.
- Use the rounded purchase estimate as a planning guide.
Formula
Roof area = footprint × √(1 + (pitch÷12)²). Waste is added, then bundles are rounded up from user-entered coverage.
Worked example
40 × 25 ft building with 6:12 pitch
Estimate roof area and bundles for a simple gable roof.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
This is a planning estimate based on your inputs and assumptions, not an exact contractor, installer, or supplier quote.