Roof Shingle Calculator

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Roof Area: 0 sq ft
Shingle Bundles Needed: 0

What is a Roof Shingle?

Roof shingles are individual overlapping pieces used to cover a roof. They provide protection against rain, wind, and sunlight while enhancing the aesthetic appeal of a house.

Shingles are typically made from materials like:

  • Asphalt (most common)
  • Wood
  • Metal
  • Slate
  • Composite materials

Among these, asphalt shingles are the most widely used due to their affordability, durability, and ease of installation.

Understanding Shingle Bundles and Sizes

How Many Shingles in a Bundle?

Shingles are sold in bundles, and three bundles usually make up one “square” (100 square feet of roof area). However, the number of shingles per bundle varies depending on the brand and type.

  • 3-tab shingles (standard type) – About 26 to 29 shingles per bundle
  • Architectural shingles (heavier and thicker) – About 21 to 24 shingles per bundle

Standard Size of a Shingle

A standard asphalt 3-tab shingle is usually 12 inches wide and 36 inches long (1 foot by 3 feet). When installed, each shingle typically covers 1 foot by 5 inches of the roof due to overlapping layers.

How to Calculate the Number of Shingles You Need

Step 1: Measure Your Roof Area

  1. Measure the length and width of each roof section.
  2. Multiply length × width to get the area of each section.
  3. Add all the sections together to get the total roof area.

For example:

  • Front side of the roof: 40 feet × 20 feet = 800 square feet
  • Back side of the roof: 40 feet × 20 feet = 800 square feet
  • Total area: 800 + 800 = 1,600 square feet

Step 2: Convert Roof Area into Squares

Roofers use “squares” to simplify shingle estimation. 1 roofing square = 100 square feet.

To calculate squares: Total Roof Area÷100=Number of Squares\text{Total Roof Area} ÷ 100 = \text{Number of Squares}

Example: 1,600 sq ft÷100=16 squares1,600 \, \text{sq ft} ÷ 100 = 16 \, \text{squares}

Step 3: Determine the Number of Bundles

Since 3 bundles = 1 square, multiply the squares by 3 to get the number of bundles needed: 16×3=48 bundles16 \times 3 = 48 \text{ bundles}

Step 4: Add Extra Shingles for Waste

  • For a simple roof (rectangle shape), add 10% extra for cutting and mistakes.
  • For a complex roof (many angles and valleys), add 15%–20% extra.

If you add 10% waste to 48 bundles: 48+(48×0.10)=53 bundles48 + (48 \times 0.10) = 53 \text{ bundles}

Final Calculation Example

If your total roof area is 1,600 sq ft:

  1. Convert to squares: 1,600÷100=161,600 ÷ 100 = 16 squares
  2. Calculate bundles: 16×3=4816 × 3 = 48 bundles
  3. Add 10% waste: 48+5=5348 + 5 = 53 bundles

You will need 53 bundles of shingles to complete your roofing project.