Convert measured rise and run among pitch ratio, slope percentage, and angle.
Inputs and method
Enter rise and run, angle, or slope percentage. The calculator converts among rise/run, arctangent angle, and 100 × rise ÷ run while retaining precision until the displayed digits are rounded.
Calculations retain full floating-point precision until the labeled display step. Counts and packages use an explicit upward ceiling only where a whole purchase unit is required.
Interpreting the estimate
Use the result as a planning value and keep input precision consistent with the measurements or source data you have. Small displayed differences can come from final-place rounding; intermediate values are not rounded.
Assumptions and limits
The output is geometry only. It does not determine roof-covering suitability, drainage design, structural capacity, access safety, or code compliance. Pitch is a direct input to a roof material takeoff, so pair it with the roofing calculator; the same rise-and-run geometry applies to the stair calculator; and to measure the roof plane first, use the square footage calculator.
Empty entries, invalid numbers, prohibited negatives, zero denominators, impossible relationships, and unsupported options trigger a validation message instead of a misleading result.