4-point saddle calculator

A four-point saddle is two offsets back to back: up and over, flat across the top, and back down. Use it when the obstruction is too wide or tall for a three-point saddle. You need the height, the width and the distance to the near edge.

Last reviewed Nov 14, 2026 · Sources at the end of the page

The 4-point saddle formula

Distance between bends = height × multiplier
Shrink per offset = height × shrink per inch
Mark 2 = distance to near edge + shrink
Mark 1 = Mark 2 − distance between bends
Mark 3 = distance to near edge + width + shrink
Mark 4 = Mark 3 + distance between bends

Each half is an ordinary offset laid out the way Greenlee, Klein and Gardner Bender describe: add the shrink when working toward the obstruction, then measure the distance between bends back toward the end. Because the first offset has already used up its shrink, everything past it — the width and the second offset — shifts by that same amount.

Worked example: 4″ high, 12″ wide box, near edge 24″ away, 30° bends

1. Distance between bends: 4 × 2.00 = 8″. Shrink per offset: 4 × ¼″ = 1″.
2. Mark 2: 24″ + 1″ = 25″. Mark 1: 25″ − 8″ = 17″.
3. Mark 3: 24″ + 12″ + 1″ = 37″. Mark 4: 37″ + 8″ = 45″.
4. Total shrink of the run past the saddle: 2″.

Bending sequence

1. Bend Mark 2 to 30°, roll 180°, bend Mark 1 to 30° — first offset done.
2. Bend Mark 3 to 30° in the same plane, roll 180°, bend Mark 4 to 30° to bring the run back down.
3. Sight down the conduit: all four bends must be in one plane, or the saddle will dog-leg.

Angle choice for saddles

30° is the usual pick because the multiplier is exactly 2. On low obstructions a 22½° saddle pulls easier; on tall ones a 45° saddle saves space. Values for each angle are on the multiplier and shrink chart.