How to use this roof pitch calculator
Roof pitch describes how steeply a roof rises relative to its horizontal run. In the United States, pitch is usually written as inches of rise for each 12 inches of run, such as 6:12. Use measured dimensions rather than estimating from a photo.
Step-by-step instructions
- Measure the vertical rise between two points on the same slope.
- Measure the horizontal run between those points, not the sloped rafter length.
- Enter both in inches and check the computed roof angle and pitch.
Calculation formula
Important assumptions and limitations
This tool assumes one straight roof plane. Measurements must be in the same units; it does not measure roofs remotely.
For material orders, confirm package yields, stock sizes and installation instructions with the actual manufacturer or supplier. Your building department determines the applicable local code; a quantity estimator is not a structural design or permit approval.
Frequently asked questions
What does a 6:12 roof pitch mean?
The roof rises 6 inches vertically for every 12 inches of horizontal distance. The angle is approximately 26.6 degrees.
Can I use this to order shingles?
Use the roof area calculator with verified building measurements. Pitch alone cannot tell you a roof's total surface area.
We publish formulas and assumptions so you can verify an estimate. Learn about our methodology or report an issue.