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4-point saddle calculator

Enter how tall and how wide the obstruction is and how far away it starts. You get all four marks and the total shrink.

Trade math for EMT benders · Free, no sign-up · Updated October 2026

Height the conduit must clear over the obstacle.

Horizontal distance from the obstacle's near edge to its far edge.

From the conduit reference (end or box) to the obstacle's near edge.

30° is the everyday default. Use 22.5° for tight spaces.

The result updates as you type.

Result

Marks 29.07 in. · 37.07 in. · 61.07 in. · 69.07 in. · shrink 2.14 in.

How it was calculated

  1. each offset's conduit length = rise / sin(30°) = 4 / 0.5 = 8 in.
  2. each offset's horizontal travel = rise / tan(30°) = 4 / 0.5774 = 6.93 in.
  3. mark 1 = distance to obstacle − horizontal travel = 36 − 6.93 = 29.07 in.
  4. mark 2 = mark 1 + offset length = 29.07 + 8 = 37.07 in.
  5. mark 3 = mark 2 + obstacle width = 37.07 + 24 = 61.07 in.
  6. mark 4 = mark 3 + offset length = 61.07 + 8 = 69.07 in.
  7. total shrink = 2 × rise × tan(30° / 2) = 2.14 in. — add to your cut length.

Assumptions

  • 4-bend saddle using 30° on all 4 bends.
  • Mark 1 → bend up; Mark 2 → return to horizontal (elevated); Mark 3 → bend back down; Mark 4 → return to horizontal at floor.
  • Bend 2 lands at the obstacle's near edge; bend 3 lands at the far edge.
  • Total shrink = 2 × (rise × tan(30° / 2)) since there are two offsets.

Basis

Trade math

This is trade math, not an NEC rule. Check the marks on your own bender before you bend.

A 4-point saddle is two offsets

The first two bends offset the conduit up and over the obstruction, and the last two bring it back down. Each pair is a normal offset, with the distance between its bends equal to the height times the angle's multiplier. The shrink is twice the shrink of one offset.

How to lay it out

  • Mark 1 starts the first offset, back far enough that the conduit clears the obstruction's near edge.
  • Mark 2 is one offset distance past mark 1.
  • Mark 3 is placed past the obstruction's far edge so the second offset clears it.
  • Mark 4 is one offset distance past mark 3.
  • Bend all four to the same angle, rolling the conduit for the second offset so it comes back down, and keep every bend in one plane.

Picking the angle

30° is the usual choice: easy math, low shrink. A 4-point saddle at 30° adds 120° of bends toward the 360° limit between pull points, so watch the total on runs with other bends.

Need every multiplier and take-up in one place? Open the conduit bending cheat sheet.

Worked example

Crossing a 4 in. tall, 24 in. wide duct that starts 36 in. from the end of the conduit, with 30° bends:

  • Obstacle rise (in.): 4
  • Obstacle width (in.): 24
  • Distance to obstacle (in.): 36
  • Bend angle (all 4 bends): 30°

Result

Marks 29.07 in. · 37.07 in. · 61.07 in. · 69.07 in. · shrink 2.14 in.

How it was calculated

  1. each offset's conduit length = rise / sin(30°) = 4 / 0.5 = 8 in.
  2. each offset's horizontal travel = rise / tan(30°) = 4 / 0.5774 = 6.93 in.
  3. mark 1 = distance to obstacle − horizontal travel = 36 − 6.93 = 29.07 in.
  4. mark 2 = mark 1 + offset length = 29.07 + 8 = 37.07 in.
  5. mark 3 = mark 2 + obstacle width = 37.07 + 24 = 61.07 in.
  6. mark 4 = mark 3 + offset length = 61.07 + 8 = 69.07 in.
  7. total shrink = 2 × rise × tan(30° / 2) = 2.14 in. — add to your cut length.

Assumptions

  • 4-bend saddle using 30° on all 4 bends.
  • Mark 1 → bend up; Mark 2 → return to horizontal (elevated); Mark 3 → bend back down; Mark 4 → return to horizontal at floor.
  • Bend 2 lands at the obstacle's near edge; bend 3 lands at the far edge.
  • Total shrink = 2 × (rise × tan(30° / 2)) since there are two offsets.

Basis

Trade math

This is trade math, not an NEC rule. Check the marks on your own bender before you bend.

Questions electricians ask

What's the difference between a 3-point and a 4-point saddle?

A 3-point saddle has one center bend and crosses round obstructions like a pipe. A 4-point saddle is two offsets with a flat section between them, for wide obstructions like a duct or beam.

How much does a 4-point saddle shrink?

Twice the shrink of one offset at the same height and angle. At 30°, that's about 1/2 in. per inch of height.

How many degrees is a 4-point saddle?

Four times your bend angle. At 30°, that's 120° toward the 360° limit between pull points.

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How this calculator was built

The bending math is standard trigonometry, and it runs the same code as the Ask Shorty iPhone app. Automated tests check every calculator against hand-worked answers. Bender marks and take-up vary by manufacturer, so check yours.

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