Construction & Materials
Roof Pitch Calculator
Roof Pitch Calculator is a browser-based calculator tool on CalcToolsBase. Free, browser-based Roof Pitch Calculator. Enter your values for an instant, clearly-labelled result - no signup, no uploads. To use it, enter your values and view the result directly in your browser — no signup and nothing to install.
Enter your rise and run and Roof Pitch Calculator works out the pitch ratio, angle in degrees, slope factor and grade with rise-over-run geometry — fast, free and private, with no sign-up or uploads.
Estimate only. Roof-pitch results depend on the measurements you enter — measure safely and double-check before ordering materials or making structural decisions.
About this calculator
The Roof Pitch Calculator gives you a quick way to work out a roof's pitch, angle and slope. Enter your rise and run; it then returns the pitch ratio, angle in degrees, slope factor and grade, worked out with rise-over-run geometry the moment you calculate. It runs fully in the browser, so it is private by design and works offline once loaded.
How to use
- Enter the rise in inches.
- Enter the run in inches, usually 12.
- Read the pitch shown as a ratio over the run.
- Tap Calculate to see the angle, slope factor, and grade.
Why use the Roof Pitch Calculator
Instant
Every quantity is worked out on your device the moment you tap Calculate.
Private
The numbers you enter stay in your browser and are never uploaded or saved.
Free
No signup, no paywall, and no ads placed inside your results.
Works offline
Once the page has loaded it keeps working on a weak or dropped connection.
Mobile-first
Laid out for phones and tablets on site just as much as for desktops.
Measure on site
Results assume the exact rise and run you enter; measure carefully on site, since small errors change the pitch and any later material take-off.
Common uses
Roof Pitch for choosing the right roofing material
Roof Pitch when measuring a roof's pitch
Roof Pitch for ordering rafters and trusses
Roof Pitch for quick rise-over-run checks
Roof Pitch for loft and attic conversions
Roof Pitch for snow-load and runoff checks
Technical notes
Roof Pitch Calculator works from rise over run: pitch = rise ÷ run (as x-in-12), angle = arctan(rise ÷ run), and slope factor = √(rise² + run²) ÷ run.
Results assume exact, idealised shapes; real-world measurement error is not included.
The tool works offline once loaded, since every computation is client-side.
Worked example
A roof rising 3 m over a 6 m run has a pitch of 3 ÷ 6 = 0.5, i.e. a 26.6° slope (arctan 0.5) or '6 in 12'.
FAQ
Is the Roof Pitch Calculator a framing design tool?
No. It converts pitch to angle, slope, and grade for reference and is not a structural or framing design.
Does the Roof Pitch Calculator send my numbers anywhere?
No. The Roof Pitch Calculator runs in your browser and nothing you enter is uploaded.
What is the slope factor used for?
Multiply a horizontal run by the slope factor to get the rafter length along the slope.
How is the angle worked out?
The angle is the arctangent of the rise divided by the run, expressed in degrees.