Roof Square Calculator
Use this calculator to estimate the total surface area of your roof in square feet and "squares" (a common roofing unit equal to 100 square feet). This helps in accurately ordering materials and estimating costs for your roofing project.
Calculation Results:
Enter your roof dimensions and pitch above to see the estimated roof area.
Understanding Roof Squares and Pitch
When planning a roofing project, one of the first steps is to accurately determine the size of your roof. This is typically measured in "squares," a standard unit in the roofing industry. One roof square is equivalent to 100 square feet of roof surface area. Knowing your roof's square footage is crucial for ordering the correct amount of materials like shingles, underlayment, and flashing, and for getting accurate quotes from contractors.
How Roof Pitch Affects Area
It's a common misconception that roof area is simply the length multiplied by the width of your house's footprint. However, roofs are rarely flat. The slope, or "pitch," of your roof significantly increases its actual surface area. A steeper roof will have a larger surface area than a flatter roof with the same footprint.
Roof pitch is usually expressed as a ratio, such as "6/12" or "8/12." This means for every 12 horizontal feet (the "run"), the roof rises 6 or 8 feet vertically (the "rise"). Our calculator uses this rise-over-run concept to accurately adjust the flat footprint area to the true sloped surface area.
The Importance of a Waste Factor
When ordering roofing materials, it's always recommended to include a "waste factor." This accounts for materials that will be cut, damaged, or simply left over during the installation process. Common waste factors range from 10% to 15% for standard gable roofs, but can be higher for complex roofs with many valleys, hips, and dormers. Our calculator allows you to input a waste percentage to give you a more realistic estimate of the materials you'll need.
How to Measure Your Roof for the Calculator
- Roof Length: Measure the total length of your roofline from end to end. For a rectangular house, this is straightforward.
- Roof Width: Measure the total width of your roofline.
- Roof Pitch: This can be trickier. You can often find your roof's pitch by going into your attic and measuring the vertical rise over a 12-inch horizontal run. Alternatively, many online resources or roofing professionals can help you determine your pitch from the ground.
- Waste Factor: A good starting point is 10-15%. If your roof has many complex features, consider a higher percentage.
By using this calculator, you can get a solid estimate for your roofing project, helping you budget effectively and communicate clearly with your roofing contractor.