By Zencalcy Editorial TeamLast reviewed About us
A rolling offset changes both height and direction, so the pipe travels on the diagonal of the two offsets. The true offset is the hypotenuse of the vertical and horizontal offsets; the travel is that true offset divided by the sine of the fitting angle, and the run is the true offset divided by its tangent.
Travel, run and cut length for a pipe rolling offset.
True offset = √(V² + H²) Travel = true offset ÷ sin θ Run = true offset ÷ tan θ
Take-out depends on the fitting: about 0.625 × nominal pipe size for a 45° elbow and 0.267 × NPS for a 22.5° elbow. Subtract two take-outs from the travel to get the pipe cut length.
| Symbol | Meaning |
|---|---|
| V, H | Vertical and horizontal offsets. |
| θ | Fitting angle. |
| Travel | Centre-to-centre diagonal length. |
The true offset is 15 in, so the travel is 21.21 in and the run 15 in. With 1-inch fittings the cut length is 21.21 − 1.25 = 19.96 in.
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An offset that moves in two planes at once — up and sideways. The pipe lies on the diagonal, so both offsets combine into one true offset.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026