How to Calculate Roof Squares from Square Feet
In roofing, materials are measured and sold in "squares." One roofing square equals 100 square feet. This guide covers the conversion and why it matters.
The Formula
Roofing Squares = Total Roof Area (sq ft) / 100
Step-by-Step Conversion
Determine your roof area in square feet
Use our Roof Area Calculator or measure manually using the roof area guide.
Divide by 100
This gives you the number of roofing squares.
Round up
Always round up to the nearest whole or half square, since you cannot buy partial squares of material.
Quick Conversion Table
| Roof Area (sq ft) | Roofing Squares | Bundles (3/square) |
|---|---|---|
| 1,000 | 10 | 30 |
| 1,200 | 12 | 36 |
| 1,500 | 15 | 45 |
| 1,800 | 18 | 54 |
| 2,000 | 20 | 60 |
| 2,500 | 25 | 75 |
| 3,000 | 30 | 90 |
| 3,500 | 35 | 105 |
| 4,000 | 40 | 120 |
Why Roofing Uses Squares
Simplified pricing
Contractors quote "per square" installed, making price comparisons easy across different roof sizes.
Material packaging
Shingle bundles, underlayment rolls, and other materials are packaged to cover whole or fractional squares.
Industry standard
All manufacturers, suppliers, and contractors speak in squares, making communication consistent.
Squares vs Square Feet -- Do Not Confuse Them
- If a contractor quotes "$350 per square," that means $350 per 100 sq ft, or $3.50 per square foot.
- A 20-square roof at $350/square = $7,000 total.
- The same roof at $3.50 per square foot = $7,000 total (same thing, different units).
From Squares to Bundles
Most standard asphalt shingles require 3 bundles per square.
Do not forget to add your waste factor (1.10 to 1.20 depending on roof complexity). For detailed bundle calculations, use our Shingle Calculator.
From Squares to Cost
Average installed costs per square in 2026:
| Material | Cost per Square (installed) |
|---|---|
| 3-Tab Asphalt | $300 - $450 |
| Architectural Asphalt | $400 - $700 |
| Metal (Standing Seam) | $1,000 - $1,800 |
| Clay/Concrete Tile | $1,000 - $2,500 |
Get a detailed cost estimate for your roof size and material using our Roof Replacement Cost Calculator.
Quick Calculator
Shingle Bundle Estimator
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