Roofing Square & Shingle Calculator
Estimate the total squares and bundles needed for your roofing project.
Estimate Summary
Total Roof Area: 0 sq. ft.
Roofing Squares: 0
Total Bundles Needed (3 per square): 0
*A "Square" in roofing is 100 square feet.
How to Calculate Roofing Materials
Calculating the amount of material needed for a new roof is critical to ensuring your project stays on budget and you don't end up with excess waste or, worse, a shortage mid-job. Professional roofers use a specific unit of measurement called a "Square."
What is a Roofing Square?
A roofing square is a unit of area equal to 100 square feet. For example, if your roof has a total area of 2,000 square feet, your roof size is 20 squares. Shingles are typically sold by the bundle, and in most cases, three bundles of shingles cover one square.
The Importance of Roof Pitch
You cannot simply measure the footprint of your house to determine roof area. Because a roof is sloped, its actual surface area is larger than the flat footprint. This is where the Pitch Factor comes in. A steeper roof has a higher multiplier. For example, a 12/12 pitch roof (a 45-degree angle) has about 41.4% more surface area than a flat roof of the same width and length.
Accounting for Waste
No roofing project is perfectly efficient. You must cut shingles to fit valleys, hips, and ridges. A standard gable roof typically requires a 10% waste factor, while complex roofs with many valleys and dormers may require 15% to 20% extra material.
Real-World Example
Suppose you have a standard gable roof measuring 40 feet long and 30 feet wide with a common 4/12 pitch:
- Base Area: 40 ft x 30 ft = 1,200 sq. ft.
- Apply Pitch Multiplier: 1,200 x 1.054 = 1,264.8 sq. ft.
- Add Waste (10%): 1,264.8 x 1.10 = 1,391.28 sq. ft.
- Convert to Squares: 1,391.28 / 100 = 13.91 Squares.
- Calculate Bundles: 13.91 x 3 = 41.73 (Round up to 42 bundles).