Conduit offset calculator

How an offset is laid out

An offset is two equal bends that move the pipe up (or over) by the rise and back to parallel. The distance between the two marks is the rise times the multiplier for the angle (the cosecant): 10° = 6.0, 22.5° = 2.6, 30° = 2.0, 45° = 1.4, 60° = 1.2. Bending also shortens the run: that shrink is about 1/16" (10°), 3/16" (22.5°), 1/4" (30°), 3/8" (45°) and 1/2" (60°) per inch of rise.

Measured to the obstruction (tape from the pipe end or last coupling to the face of the obstruction): mark A = distance + shrink. Bend A first with the hook facing the obstruction, then slide back to mark B = A − between marks, roll the pipe 180° and bend again.

Measured to the start of the offset: mark A = distance, mark B = A + between marks, both with the hook toward the end and the pipe rolled 180° for the second bend.

Example: a 10" rise at 30° with the obstruction 48" from the end gives 20" between marks and 2-1/2" shrink, so mark A is at 50-1/2" and mark B at 30-1/2".