Roofing Calculator: The Complete Guide
Estimate your roofing materials. Enter the roof's length and sloped width to get the area in roofing squares and the number of shingle bundles needed, with waste included.
Who the Roofing Calculator is for
Homeowners and roofers estimating shingles for a re-roof or new roof.
How to use the Roofing Calculator
- Type your values into the fields above — pick your currency or units where the calculator offers them.
- Results update automatically as you type; there's no submit button and nothing is sent to a server.
- Adjust any input to compare scenarios, then copy the result with a single click.
How it works
Roof area = length × sloped width. A roofing 'square' is 100 ft². Shingle bundles ≈ squares × 3, plus about 10% for waste, starter, and ridge.
Features
- Roofing squares
- Shingle bundles
- 10% waste included
- Imperial or metric
Measuring a roof
Roofing is estimated in 'squares' — each 100 square feet of roof surface. Measure the sloped area (not the flat footprint), since the pitch adds surface. Most shingles come three bundles to a square. Add about 10% for waste, the starter course, and ridge caps.