How to use this calculator
Convert rise and run to slope and angle. Enter rise (inches), horizontal run (inches). The result updates when you change an input. To compare two sets of inputs, save scenario A, then enter the second set; the result panel shows the difference.
Formula and limits
Pitch per 12 = rise/run × 12. Angle = arctan(rise/run). This is geometry, not a structural assessment.
Worked example
The following example uses the calculator’s starting values. It is an illustration of the method, not a recommended target.
| Input | Example value |
|---|---|
| Rise (inches) | 6 |
| Horizontal run (inches) | 12 |
Rise per 12 units of run: 6
Angle: 26.565°
Interpreting your result
Confirm actual dimensions, supplier specifications, and site conditions. Quantity estimates do not establish structural adequacy or compliance with building codes. Waste allowances are user assumptions.
Comparing alternatives
Save the first result as scenario A, then change one input. The comparison shows the numeric difference; it does not label either result as better. Choose inputs that describe realistic alternatives. Values shown on screen are rounded, so calculations from rounded intermediate results may differ slightly.