Roofing, Insulation & Exterior calculator
Roof Pitch Calculator
Calculate roof pitch from rise and horizontal run, returning angle, percentage and rise-to-run ratio.
Calculate roof pitch from rise and horizontal run, returning angle, percentage and rise-to-run ratio. Keep the dimensions and units consistent, then check the figures that describe the product or layout you will really use. In this calculation, rise and horizontal run can change the answer materially. Rise and run must use the same units. The calculated pitch describes geometry only; it does not confirm that a roofing product is suitable for that pitch.
What you need to enter
The Roof Pitch Calculator uses the following project information to calculate the result.
- Rise
- Run
Calculator result
Pitch angle, ratio and percentage
How the Roof Pitch Calculator works
To produce pitch angle, ratio and percentage, the Roof Pitch Calculator applies atan(rise/run) and equivalent formats. The engine is configured for roof pitch expressed as angle, percentage and rise-to-run ratio, not as a generic text estimate. Check rise and horizontal run, since an incorrect value there can materially change the result.
Roof Pitch Calculator worked example
Roof Pitch Calculator example: A roof with 600 mm rise over 1,200 mm horizontal run has a 50% slope and an angle of about 26.6°. The same geometry is commonly described as approximately 6-in-12 pitch. The worked figure becomes more useful when rise and horizontal run is taken from the real product or site rather than a generic default.
Important calculation assumptions
For roof pitch expressed as angle, percentage and rise-to-run ratio, rise and run must use the same units. The calculated pitch describes geometry only; it does not confirm that a roofing product is suitable for that pitch.
Frequently asked questions
How can I prepare the job data for the Roof Pitch Calculator?
Measure vertical rise and horizontal run over the same span, using the same units for both. The Roof Pitch Calculator then applies those figures to roof pitch expressed as angle, percentage and rise-to-run ratio.
What if my assumption for rise and horizontal run is wrong in the Roof Pitch Calculator?
Rise and run must use the same units. The calculated pitch describes geometry only; it does not confirm that a roofing product is suitable for that pitch. Treat the assumptions behind rise and horizontal run as project-specific in the Roof Pitch Calculator.
How should I use the Roof Pitch Calculator result when choosing roof materials?
For the Roof Pitch Calculator, after calculating, use the pitch as a geometry input for roof area and product-suitability checks. Verify that the chosen roof covering is permitted at the calculated pitch.