Conduit BendingBy Blissom · Updated 2026-10-23
Layout values: check them against your own bender, on scrap first.
Short answer: marks 1–2 and 3–4 are offsets of the saddle depth (30°: 2 × depth apart). Mark 2 goes at the near edge minus the clearance plus one offset's shrink; mark 3 is the width plus both clearances after mark 2. Using Klein's rounded 30° rule, estimate 1/4" of shrink per inch of depth on each side, about 1/2" per inch for the whole saddle.
How to lay out a 4-point saddle
- Measure the depth: the rise the conduit centerline needs above its original path, enough for the outside of the conduit to clear the obstruction. Then the width along the run, and the clearance you want before and after it.
- Find the offset spacing: depth × multiplier (30° = 2, 22.5° = 2.6, 45° = 1.4).
- Mark bend 2 at the near-edge distance minus the near-side clearance, plus one offset's estimated shrink. This is the bending reference mark, not necessarily where the curve ends and the conduit reaches full height, so check that on your bender before the first bend.
- Mark bend 1 one offset spacing before bend 2, bend 3 the width plus both clearances after bend 2, and bend 4 one offset spacing after bend 3.
- Bend 1 on mark 1 with the arrow. Rotate the conduit 180° and make bend 2 on mark 2, back to level: that is the first offset.
- Bend 3 on mark 3 without rotating, so it turns the conduit back down toward the original line. Rotate 180° again and make bend 4 on mark 4, back to level. Keep all four bends in one plane and use the same bender reference mark for each; hook direction differs by maker, so follow your bender's guide.
The marks are nominal. Each bend has a radius, so the level top between bends 2 and 3 comes out shorter than the 2-to-3 mark spacing, and how much depends on the shoe. When clearance is tight, check where bend 2 ends and bend 3 starts against the obstruction before making bend 3.
Worked example: 3" deep, 8" wide duct at 30° (rounded trade values)
Assumes 1" clearance on both sides and the arrow on every mark. Check the actual clearance with your bender before installing.
- Offset spacing: 3 × 2 = 6". Shrink per side: 3 × 1/4" = 3/4".
- The near edge of the duct is 30" from the end and you want 1" clearance: bend 2 at 30 − 1 + 3/4 = 29-3/4".
- Bend 1: 29-3/4 − 6 = 23-3/4".
- Bend 3: 29-3/4 + 8 + 2 = 39-3/4". Bend 4: 39-3/4 + 6 = 45-3/4".
- Total shrink: 1-1/2".
Handling shrink
Only the shrink of the first offset moves the marks toward the obstruction. The second offset shrinks the conduit after the saddle, which matters when the far end has to land on something (a box, a coupling), so take the total shrink into account when you cut the stick. The shrink figures are Klein's rounded field values; the sharp-corner geometry gives a little more (1.61" for a 3" saddle at 30°, against 1-1/2"), and a real bend differs again.
Bend budget and code
| Bend angle | Four bends total |
|---|---|
| 22.5° | 90° |
| 30° | 120° |
| 45° | 180° |
All bends between pull points count toward 360° (NEC 2023 358.24(B) for EMT (358.26 in NEC 2020); the 2026 NEC adds 300.24 for runs that combine raceway types), so include the other bends in the run. Bends must not damage the tubing or effectively reduce its internal diameter (358.24(A)), and Chapter 9, Table 2 gives the minimum centerline radius. Use a bender rated for the conduit type and size, follow its instructions, and check the finished bends for flattening or damage.
Method
The calculator applies the offset multipliers and shrink allowances from Klein's bender guide to two opposing offsets; the four-point layout is derived from those offset values. Mark 2 lands at the near edge minus the clearance plus one offset's shrink, the same rule as an offset that must be finished at a fixed point. Finished geometry depends on the shoe, so confirm it on your bender.
3-point or 4-point?
A 3-point saddle is faster (three bends) and is often enough over a narrow obstruction such as a pipe, where its peak gives the clearance. Choose a 4-point saddle when a wider or flat-topped obstruction needs a level crossing; check the finished geometry either way.
Mistakes
- Forgetting the clearance on the far side, so bend 3 lands on the obstruction.
- Bending 3 and 4 in the wrong direction: the second offset must come back down to the original line.
- Unequal angles, which leave the far end higher or lower than the start.
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
What angle should I use for a 4-point saddle?
30° is most common. 22.5° works for shallow saddles and pulls easier; 45° keeps the saddle short when space is tight. All four bends must be the same angle, and the saddle adds four times that angle toward the 360° limit.
Why does my saddle sit on the obstruction even though the marks were right?
The marks set where the bends are, not how long the straight top ends up. Each bend has a radius, so the level section between bends 2 and 3 is shorter than the mark spacing. Add clearance or use a shallower angle, and check the available space before the first bend and the finished top before bending 3 and 4.
When should I use a 4-point saddle instead of a 3-point?
A 3-point saddle is often enough for a narrow obstruction such as a pipe, where its peak gives the clearance. Choose a 4-point saddle when a wider or flat-topped obstruction, like a duct, a beam flange or a cable tray, needs a level crossing. Check the finished geometry either way.
All four marks from the end of the pipe
- Enter the distance to the near edge and the clearance each side
- Marks from the end with the shrink already in, corrected for your shoe
- Every mark shows which way the hook faces
- Warns when the flat top is too short for your bender
Android only. There is no iPhone version yet; the free calculators on this site work on any phone.
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