How Many Shingles for a 1,000 sq ft Roof at 12/12 Pitch
Calculate shingles for a steeply pitched 1,000 sq ft roof (25×40 ft) with a 12/12 pitch and 15% waste.
How to use this tool
- Enter the roof's horizontal length and width (one side) in feet.
- Set the pitch multiplier (6/12 pitch is about 1.12).
- Add a waste allowance of 10–15% for cuts around hips and valleys.
- The result shows total roof area, squares, and bundles to purchase.
A 12/12 pitch is the steepest common residential slope and nearly doubles the actual roof surface area — plan carefully with this calculator.
Frequently asked questions
- What is a roofing square?
- A roofing square equals 100 square feet of roof surface. Standard shingles come in bundles, and 3 bundles cover one square.
- How many bundles of shingles per square?
- Most standard 3-tab or architectural shingles require 3 bundles per square (100 ft²). Heavy-weight shingles may require 4 bundles per square.