Conduit BendingBy Blissom · Updated 2026-10-23
Layout values: check them against your own bender, on scrap first.
Short answer: shift = center-to-center spacing × tan(bend angle ÷ 2). At 10° the factor is 0.087, at 22.5° 0.199, at 30° 0.268, at 45° 0.414 and at 60° 0.577. Move both marks of every following conduit by one more shift than the one before it.
Why parallel offsets need a shift
If every conduit in a rack is marked in the same place, the bends start side by side. The conduit on the outside of the bend then crowds its neighbor inside the offset and the spacing pinches. Starting each outer conduit's bends a little later helps keep the center spacing consistent through the offset. The shift is a layout approximation; the actual spacing at the bends depends on the bender radius and workmanship.
How to bend a rack of offsets
- Lay out conduit 1 (the one on the inside of the offset) as a normal offset.
- Work out the shift for your center spacing and angle.
- Mark conduit 2 with both marks moved one shift farther along; conduit 3 two shifts; and so on.
- Bend every conduit to the same angle with the same bender orientation, and check the rack with a straightedge.
Shift per conduit by spacing and angle
| Center spacing | 10° | 22.5° | 30° | 45° | 60° |
|---|---|---|---|---|---|
| 1" | 1/16" | 3/16" | 1/4" | 7/16" | 9/16" |
| 1-1/2" | 1/8" | 5/16" | 3/8" | 5/8" | 7/8" |
| 2" | 3/16" | 3/8" | 9/16" | 13/16" | 1-1/8" |
| 2-1/2" | 3/16" | 1/2" | 11/16" | 1-1/16" | 1-7/16" |
| 3" | 1/4" | 5/8" | 13/16" | 1-1/4" | 1-3/4" |
| 4" | 3/8" | 13/16" | 1-1/16" | 1-11/16" | 2-5/16" |
| 6" | 1/2" | 1-3/16" | 1-5/8" | 2-1/2" | 3-7/16" |
Worked example: three conduits on 2" centers, 6" offset at 30°
- Conduit 1, on the inside of the offset: a normal 30° offset, marks 12" apart (6 × 2), shrink 1-1/2".
- Shift per conduit: 2" × tan 15° = 0.536", about 9/16".
- Conduit 2: both marks 9/16" farther along than conduit 1. Conduit 3: 1-1/16" farther along.
- Bend all three to the same angle, keeping the bend plane and the bender reference the same. The shifts keep the center spacing close to 2" through the bends; check the actual spacing and clearance at both bends before installing.
The formula
In the idealized layout, each outer conduit's bend is staggered from the inner one by the center spacing times the tangent of half the bend angle, the same geometry that gives offset shrink. Real shoes bend every conduit on the same finite radius, so the arcs are not perfectly concentric: check the finished fit. See the formulas.
Mistakes
- Shifting in the wrong direction, which makes the spacing pinch instead of stay even.
- Shifting only the first mark: both marks of each conduit move by the same amount.
- Mixing angles or benders in one rack. Every conduit must be bent the same way.
Sources: NEC 2023 358.24 and Chapter 9, Table 2; Klein Tools Conduit Bender Guide (stub take-up, offset multipliers and shrink, saddles). Method.
Questions electricians ask
How do you calculate parallel offsets?
Lay out the first conduit as a normal offset. Then shift both marks of each following conduit by center-to-center spacing × tan(half the bend angle). At 30° that factor is 0.268, so 2" centers give a 9/16" shift per conduit.
Which way do the marks move for parallel offsets?
Toward the outside of the offset: each conduit farther from the inside of the bend gets its marks moved farther along the run, so its bends start later and the conduits stay approximately evenly spaced through the offset.
Do parallel kicks use the same formula?
For equal-angle single kicks bent in the same plane, the same half-angle shift can stagger the kick marks. Kicks combined with 90° stubs need more layout measurements, and this calculator covers parallel two-bend offsets, not complete kick assemblies.
Every conduit in the rack, marked
- Both marks for every conduit, measured from the end of the pipe
- Offset spacing and shrink corrected for your bender
- Parallel kicks too, with the same adjustment
- Save the rack as a job and share a PDF with the crew
Android only. There is no iPhone version yet; the free calculators on this site work on any phone.
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