🔧 Rolling Offset Calculator
Calculate the true offset, travel, and run for a rolling offset pipe fitting from the roll, set, and fitting angle.
What this calculator does
A rolling offset happens in pipefitting when a pipe must change direction in two planes at once — both vertically (the “set”) and horizontally (the “roll”) — rather than a simple offset in a single plane. This calculator finds the true offset distance and the resulting travel and run lengths for the diagonal connecting pipe.
The formula
The true offset is the straight-line distance combining both the roll and set measurements, found using the Pythagorean theorem: True Offset = √(roll² + set²). Once the true offset is known, it is treated like a simple offset: Travel (the actual diagonal pipe length between fittings) = True Offset ÷ sin(fitting angle), and Run (the straight-line horizontal distance the offset spans) = True Offset ÷ tan(fitting angle).
- Common fitting angles are 45°, 22.5°, 11.25°, and 60°, matching standard pipe fitting angles.
- Roll and set should be measured center-to-center between the two pipe runs, in the same units.
This tool is for general pipefitting planning and educational purposes; always verify layout measurements on the job before cutting pipe.