Shingle Calculator
Use this calculator to estimate the number of roofing squares and shingle bundles you'll need for your project. Accurate measurements and accounting for roof pitch and waste are crucial for a successful roofing job.
Results:
Estimated Roof Surface Area: 0 sq ft
Estimated Roofing Squares Needed: 0
Estimated Shingle Bundles Needed: 0
Understanding Your Shingle Needs
Replacing or installing a new roof is a significant home improvement project. One of the first and most critical steps is accurately estimating the amount of roofing material you'll need. This not only helps you budget effectively but also prevents costly delays from ordering too little or wasting money on too much.
What is a Roofing Square?
In roofing, materials are often measured in "squares." A roofing square is a unit of measurement equal to 100 square feet (10 ft x 10 ft). Shingles are typically packaged in bundles, and it usually takes 3 bundles to make one square, though this can vary slightly by manufacturer and shingle type. Our calculator uses a default of 3 bundles per square, but you can adjust this if your specific shingles differ.
How to Measure Your Roof
- Roof Length and Width: For a simple gable roof, measure the length of the roofline (e.g., from one end of the house to the other) and the width (e.g., from the eave to the peak). If your roof has multiple sections or complex shapes, you'll need to break it down into simpler rectangles and triangles, calculate each area, and then sum them up.
- Roof Pitch: This is the steepness of your roof, expressed as a ratio (e.g., 4/12). It means the roof rises 4 inches vertically for every 12 inches it runs horizontally. A steeper roof has a larger surface area than a flat roof with the same footprint. Our calculator includes common pitch multipliers to adjust for this. You can often find your roof's pitch by measuring from inside your attic or by using a pitch gauge on the exterior.
The Importance of a Waste Factor
It's almost impossible to install a roof without some material waste. Shingles need to be cut to fit edges, valleys, hips, and around chimneys or vents. Mistakes can also happen. A waste factor accounts for this. For simple roofs, a 10% waste factor is common. For more complex roofs with many valleys, hips, or dormers, you might consider a 15-20% waste factor. Our calculator defaults to 10% but allows you to adjust it based on your project's complexity.
Example Calculation:
Let's say you have a roof that is 40 feet long and 25 feet wide, with a standard 4/12 pitch, and you want to include a 10% waste factor. Each square requires 3 bundles.
- Footprint Area: 40 ft * 25 ft = 1000 sq ft
- Pitch Multiplier (for 4/12): 1.054
- Actual Roof Surface Area: 1000 sq ft * 1.054 = 1054 sq ft
- Base Squares: 1054 sq ft / 100 sq ft/square = 10.54 squares
- Squares with Waste: 10.54 squares * (1 + 10/100) = 10.54 * 1.10 = 11.594 squares
- Bundles Needed: 11.594 squares * 3 bundles/square = 34.782 bundles
- Rounded Up Bundles: You would need to purchase 35 bundles.
Using our calculator with these inputs will give you these precise results, helping you plan your roofing project with confidence.