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Roofing Calculator

Our roofing calculator will provide detailed and accurate estimations on bundles, rolls, and felt for your next job at the click of a button. Plus send it to you in an easy to read email so you don’t lose track of it.

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Roofing Calculator


122,608,100 roofs scanned by our roofing calculator in the United States


Our roof replacement cost calculator has determined the average price of a roof in the USA is $7,662


Find a roofer to service your home from 44,227 highly rated roofing contractors nationwide

Instant Roofer’s Roofing Calculator

Our roofing calculator is the perfect tool for you to use when you’re estimating the amount of materials needed for your next roofing job. Working with a nonstandard angle on a roof? No problem! Just use our manual roofing calculator and enter the custom angle you’re working with. By taking the base area, the rise, roof angle, and the amount the eaves stick out, we are able to provide an accurate estimation that makes quoting for your future projects simple and quick!

Diagram of how our roofing calculator works and how to measure your roof to use it.

Our Roofing Tool Provides:

  • An accurate estimate of square footage (including eaves) 
  • The estimated price for materials based on your specifications. 
  • How many rolls of roofing material you will need
  • As well as a suggestion for a 10% buffer (for customizations)
  • Amount of composition shingle bundles
  • And the amount of #15 felt and #30 felt recommended
Roofing calculator with detailed results

Plus it comes with an option of emailing the results in a plain text file straight to your phone, so you can pull it up and forward it wherever you need!

Roofing calculator with email report function

Understand that the provided area calculation is an approximate figure. While it’s extremely close, it’s best to verify with your clients in case a roof has intricate designs or potential underlayment issues. Detailed measurement of each roof section’s dimensions and areas helps drill down a precise area and cost estimation. If the roof you’re working on has many custom or intricate designs or features, make sure you order enough material by checking in person. 

The Area Calculator is designed to evaluate the area of various basic shapes, which, when combined, accurately represent the roof’s total area. This refined calculation method improves the accuracy of the roof area.

We also customize the estimation further by allowing roofers to input the prices of materials so that the cost estimation is even more accurate. Depending on the vendor each roofing contractor works with and the geographic location of the roof being replaced, it can greatly impact the cost of the project and the quality of roofing leads gathered.

Custom Roofing Calculator

Understanding Roof Pitch

Understanding roof pitch is crucial for homeowners and contractors alike because it refers to how steep a roof is. Since it measures the roof’s vertical rise over its horizontal span, roofers know how to approach a roof replacement regarding safety and homeowners can be in the know when it comes time to replace a roof. While similar to slope, roof pitch specifically denotes how many inches the roof rises for every 12 horizontal inches. In the U.S., this measurement standard means a 7/12 roof pitch rises 7 inches for every 12 inches it runs. Internationally, the pitch is often expressed in degrees.

Roof pitch influences how easily you can walk on the roof, its drainage efficiency, and its ability to withstand heavy rain or snowfall, with steeper pitches generally found in regions prone to such conditions. Roofs can be influenced by the climate as well. Flat roofs in hotter climates for efficient water draining and steeper roofs in colder climates to encourage snowmelt and rain runoff.  

Moreover, the pitch impacts the actual roof area, critical for accurately calculating material needs. Horizontal measurements, whether from plans or images, require adjustment using a pitch-specific correction factor to find the roof’s true area. This step is essential for a precise estimate of materials needed, as shown in the correction factor table. The table illustrates that the larger the roof pitch, the more significant the difference between the measured area and the actual roof area, reaching up to a 2.236 factor at a 24/12 pitch.

To ensure the most accurate material estimation, it’s advisable to measure each roof section’s area and pitch, applying the respective correction factor. This detailed approach, while more complex, guarantees the most effective planning and utilization of roofing materials, optimizing both cost and construction efforts for your roofing project.

PitchDegreesMultiple FactorPitchDegreesMultiple Factor
Roof Pitch Multiplier Table

Measuring Roof Pitch

You can use our interactive and free roof pitch calculator to see what the pitch of your roof is via Google Street View. Or you can do it manually.

Measuring Roof Pitch Manually

Measuring the pitch of your roof manually can be done relatively easily with some basic tools and math. Here’s a step-by-step guide on how to measure your roof’s pitch:

  1. Safety First:
    • Before you start, ensure that you have a safe way to access your roof. You might need a ladder, and it’s best to have someone with you to hold the ladder steady. Always take precautions to prevent falls or other injuries.
  2. Tools You’ll Need:
    • A level (at least 12 inches long)
    • A measuring tape
    • A pencil or marker
  3. Measuring the Pitch from the Roof:
    • Place the end of the level against the roof surface so it’s sticking out horizontally.
    • Make sure the bubble in your level is centered, indicating that the level is perfectly horizontal.
    • From the 12-inch mark on the level, measure vertically down to the roof. The number of inches you measure is the rise.
    • The run is the horizontal distance covered by the level, which is 12 inches if you’re using a 1-foot level.
    • This gives you the rise over run, which is the pitch of the roof. For example, if the vertical measurement from the level to the roof is 7 inches, your roof’s pitch is 7/12.
  4. Measuring the Pitch from the Attic:
    • If you prefer not to climb onto the roof, you can measure the pitch from your attic.
    • Find a place where you can see a rafter, and position your level horizontally against the rafter.
    • Measure 12 inches along the rafter from where your level begins, then from that 12-inch point on the rafter, measure vertically up to the underside of the roof. This will give you the rise.
    • The run is the 12-inch distance you marked on the rafter.
  5. Use of a Roof Pitch Calculator:
    • If manual measurement sounds too cumbersome, there are online roof pitch calculators that can help simplify the process. You will still need the rise and run measurements to use them effectively.

Remember, if you’re uncomfortable with heights or the roof is too steep, it’s always best to hire a professional to do the measurement for you. Safety is more important than anything else.

Roofing Calculator FAQs

What is roof pitch, and why is it important in calculating roof size?

Roof pitch is the angle of your roof’s slope, defined by the vertical rise over the horizontal run. It’s crucial for calculating the roof size because it affects the actual surface area of the roof. Taller (or steeper) roofs will have more material because the material must run up the slope instead of just across the top of the home.

What is the most common roof pitch?

The most common roof pitch is between 10 and 25 degrees. Take a look at the roof and see if it seems more flat or steeper. If you live in a hotter climate, the pitch will likely be lower! 

How can I manually measure my roof’s pitch?

The easiest way to do this is to go into your attic, find a rafter, and use a 12 inch carpenter’s level to create a right angle triangle. The bottom of the triangle will be 12 inches (the length of the level) and the side extending to the rafter will be whatever your slope is. For example, if it’s 6 inches, then your roof’s pitch is 6/12. 

How accurate are the roofing calculator results?

Our roof material estimation calculator is designed to work with a variety of roof types including gable, hip, and mansard roofs. Our 10% buffer should cover most unexpected issues that come up, but if you’re working with an intricate or custom roof, it’s always best to do a physical inspection so you can double check. 

What’s the difference between the manual and AI-powered roof calculators?

The manual calculator requires you to input measurements to calculate the roof area, while the AI-powered calculator can provide estimates based on provided data and intelligent analysis. Both are incredibly powerful tools for roofing contractors and homeowners alike. 

Do I need to know my roof’s pitch to use the roofing calculators?

Knowing your roof’s pitch is required to get a truly accurate estimation since the pitch of your roof can greatly impact the overall surface area of the roof. When using our A.I. powered calculator, it can provide predominant pitch automatically in some states though! 

What should I do if my roof has multiple levels or unusual shapes?

If your roof has multiple levels, intricate designs, and unique features, the best option would be to separate the roof into manageable sections and calculate them independently first, then add those estimations together. Getting an in-person inspection can also help iron out exactly what the real cost could be.