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Conduit offset calculator
Conduit Offset Calculator: Bend Spacing & Shrink
Enter the offset depth and bend angle to calculate center-to-center bend spacing and shrink using a published field table. The result deliberately stays separate from bender-specific stub deduct and alignment marks.
Two-bend offset
Spacing = offset depth × multiplier. Shrink = offset depth × published shrink factor. Both bends use the same selected angle in opposite directions.
Calculate conduit offset spacing & shrink
Published field constants used
| Angle | Multiplier | Shrink factor |
|---|---|---|
| 10° | 6.0 | 1/16 per unit of depth |
| 15° | 3.86 | 1/8 per unit |
| 22.5° | 2.6 | 3/16 per unit |
| 30° | 2.0 | 1/4 per unit |
| 45° | 1.4 | 3/8 per unit |
| 60° | 1.2 | 1/2 per unit |
Worked example: 4-inch offset at 30°
Choose 30° and an offset depth of 4 inches. The Greenlee table uses a 2.0 multiplier, so the bend marks are 8 inches center-to-center. The shrink factor is 1/4 inch per inch of offset, so total shrink is 1 inch.
The calculator does not decide which mark on your hand bender or powered shoe should be aligned for the first bend. That step is bender-specific.
Choosing an angle is a layout decision
Shallower angles spread the offset over more conduit and reduce the shrink factor; steeper angles shorten the required spacing but increase shrink and can make the bend path more abrupt. Jobsite space, pull considerations, conduit type and the actual bender procedure all matter.
For the full field table and explanation, see the Conduit Bending Chart & Calculator.
Need to clear one centered obstruction?
Use the 3-Point Saddle Calculator for Greenlee's published 45° center / 22.5° outer-bend saddle layout, including mark spacing and shrink.
Technical source
- Greenlee — 884 and 885 Hydraulic Benders operator manual — offset multiplier and shrink table used by this calculator.
Frequently asked questions
How do you calculate the distance between conduit offset bends?
Multiply the offset depth by the field multiplier for the selected equal bend angle. For 30-degree bends, the Greenlee table uses a 2.0 multiplier.
How much does a 30 degree offset shrink conduit?
The Greenlee table lists 1/4 inch of shrink per inch of offset depth at 30 degrees.
Can I use millimetres in the offset calculator?
Yes. The multiplier and shrink ratios are dimensionless, so the same calculation works in millimetres as long as the input and output units stay consistent.
Does this calculator tell me where to align the bender arrow?
No. It calculates offset spacing and shrink. Alignment marks, stub deduct, gain and springback procedures belong to the specific bender/shoe instructions.