Our free Roof Area Calculator is designed for simplicity. Follow these steps to get your estimate:
- Enter Roof Length: Measure the horizontal length of your roof in feet. For a simple gable roof, this is the length of the ridge line.
- Enter Roof Width: Measure the width of your roof in feet, from one eave (the edge of the roof) to the other. Remember to include any overhangs.
- Select Your Roof Pitch: Choose the pitch that most closely matches your roof’s steepness.
Once you enter these values, the calculator will instantly provide an estimated total area for your roof.
Roof Area Calculator
Enter your roof dimensions to estimate the total area.
What is Roof Pitch?
Roof pitch, or slope, is the most important factor for an accurate calculation. It describes the steepness of your roof. In the United States, pitch is typically expressed as a ratio of “rise” over “run.”
- Run: This is a standard horizontal distance, always set at 12 inches.
- Rise: This is the vertical distance the roof goes up for every 12 inches of horizontal run.
For example, a 4:12 pitch means the roof rises 4 inches for every 12 inches it runs horizontally. A roof with a 12:12 pitch has a perfect 45-degree angle.
Why does pitch matter so much? A pitched roof has a larger surface area than the flat floor area it covers.
The steeper the pitch, the greater the surface area. The calculator uses a “pitch multiplier” or “slope factor” based on your selection to adjust the flat dimensions and find the true inclined surface area.
Why Accurate Measurements Are Crucial
Getting your roof area calculation right is essential for several reasons:
- Cost Management: Accurate measurements prevent you from over-ordering expensive materials or, even worse, not ordering enough and causing project delays.
- Material Estimating: Every shingle, tile, and underlayment panel counts. A precise area helps you create a reliable material list.
- Project Planning: Knowing your roof’s total area is the foundation for a well-organized project, from creating a timeline to hiring the right roofing contractor.
It’s also important to factor in waste. Simple gable roofs usually require adding about 10% extra material for cuts and scraps.
More complex roofs with features like hips, valleys, or dormers may need a waste factor of 15% or more.
Get Started on Your Next Project
Figuring out your roof’s dimensions doesn’t have to be complicated. An online roof area calculator gives you the confidence to plan your project effectively, ensuring you have the right information for budgeting and material purchasing.
By understanding the basics of length, width, and pitch, you can move forward with your roofing project with a clear and accurate plan.