Practical measurements for roofing projects
RoofPitch HQ provides free roofing calculators and measurement guides for U.S. homeowners and small roofing contractors. Use the site to understand a roof measurement, check the geometry behind an estimate, or prepare clearer questions for a roofer or supplier. No account is required to use the calculators.
The tools use inches, feet, and square feet. Results update as you enter measurements, with labels that distinguish horizontal run from sloping length and projected area from actual roof surface. That distinction matters whether you are reviewing a roof plan or checking notes on a phone.
Choose the tool for your measurement
Start with the roof pitch calculator to convert rise and run, an angle, or a slope percentage. The roof area calculator applies pitch to horizontal roof dimensions. Separate tools estimate a common rafter's reference length and shingle quantities, with the relevant assumptions explained beside the results and in the page instructions.
If you need to collect the measurements first, follow the roof pitch measurement guide. It explains what rise and run refer to and includes an attic method that avoids going onto the roof. The pitch comparison chart helps you compare familiar ratios, angles, and percentages.
Clear calculations and stated assumptions
Each calculator explains its inputs, the calculation it performs, and what its result includes. Worked examples use the same calculation functions as the tools. Displayed numbers are rounded for readability; the calculations retain precision until the final formatting or whole-bundle rounding step.
An estimate is only as useful as its measurements and assumptions. A symmetrical gable, a single pitch across a projected area, or an assumed bundle coverage may not describe every roof. Check those conditions before applying a result to an addition, a complex roof shape, or a particular roofing product.
Guidance you can check
The guides link to supporting material from roofing manufacturers, building-code publishers, and building-science resources. These sources help explain material slope limits, installation conditions, and measurement methods. Follow the linked instructions for the exact product and check the requirements adopted in your location.
RoofPitch HQ does not inspect your roof or determine its structural capacity. Calculator results do not replace an on-site inspection, a framing design, manufacturer installation instructions, or a contractor's material takeoff. Pitch alone also cannot tell you whether a roof is safe to access.
Help make the information clearer
If a result seems wrong or a guide is unclear, visit the contact page. Include the page, inputs, units, and result so the issue can be reproduced and the explanation checked.