Roof pitch calculator — convert rise/run, degrees and percent.
Roof pitch can be expressed in several formats. Converting them correctly is the first step before calculating ridge height, rafter length and the geometry of roof-framing cuts.
Convert roof pitch between rise/run, degrees and percent.
Use any consistent unit for rise and run. The ratio is unit-independent.
Three common ways to describe roof pitch
Rise/run: a ratio such as 6:12 means the roof rises 6 units for every 12 units of horizontal run.
Degrees: the geometric angle between the roof line and horizontal.
Percent: rise divided by run, multiplied by 100.
Convert rise/run to degrees
angle = arctan(rise ÷ run)
Because the calculation is a ratio, the same formula works in metric and imperial units as long as rise and run use the same unit.
Convert degrees to slope
rise/run ratio = tan(angle)
Once the ratio is known, it can be applied to the horizontal run to calculate the vertical rise.
Why pitch affects the whole framing model
Pitch changes ridge height, common-rafter length, hip-rafter geometry, jack-rafter lengths, plumb-cut orientation and the spatial relationship between supporting elements. It should therefore be one shared project parameter.
Roof pitch in Krokwio
Krokwio uses the selected roof geometry throughout the project instead of recalculating each element independently. The same slope feeds the model, element geometry and workshop information.
Related: Ridge Height Calculator, Rafter Calculator.
Turn roof geometry into workshop-ready information.
Use one project for geometry, 2D/3D views, element cards, cutting data, PDF documentation and QR identification.