Conduit Offset Calculator
Calculate standard and rolling-offset geometry, bend spacing, rotation, and theoretical shrink.
Conduit bending geometry
Configure the offset
Project information for worksheet
Geometry preview
Two-bend offset
Bend angle is drawn to scale. Lengths are proportionally normalized to fit the preview.
Calculated result
Offset dimensions and formulas
Formula breakdown
True offset: 12 in
Multiplier: 1 ÷ sin(30°) = 2.0000
Ideal travel: 12.000 × 2.0000 = 24.000 in
Common field-table shrink: 12.000 × 0.2500 = 3.000 in
Exact geometric shrink: 12.000 × tan(15°) = 3.215 in
Conduit offset guidance
Use geometric results with the bender's instructions
A standard offset moves conduit in one plane. A rolling offset combines a vertical rise with a horizontal roll before applying the bend-angle multiplier. These formulas describe ideal centerline geometry; they do not replace tool-specific take-up, bend-radius, springback, or field-marking instructions.
What is the offset multiplier?
The multiplier is one divided by the sine of the selected bend angle. Multiply the true offset by this value to obtain the ideal centerline travel between two equal bends.
How is a rolling offset calculated?
The calculator combines vertical rise and horizontal roll using the Pythagorean theorem. It then applies the selected bend-angle multiplier to that true offset and calculates the rotation direction with atan2.
Is the calculated travel the exact distance between field marks?
The calculator now provides first and second planning marks using the published common shrink factor and ideal travel. Exact field marks can still depend on the bender, shoe radius, take-up, gain or deduct method, conduit springback, and manufacturer instructions.
What does theoretical shrink mean?
Theoretical shrink is the geometric reduction along the original run caused by the offset. The calculator uses true offset multiplied by the tangent of half the bend angle. Field results can vary with the bending method and equipment.
Review formulas and assumptions on the methodology page.