CONDUIT BENDING
About this calculator
This conduit bending calculator handles the two bends every electrician runs daily: the offset (two opposite bends to step a run around an obstruction) and the 3-bend saddle (center bend at 2× the side bends to clear an obstacle in the middle of a run). Pick the bend angle and rise/obstacle height — the calculator returns the distance between marks, the shrink (how much the run loses to the bends), and where to start the first mark from a known reference. Multipliers come from the standard bender table: 22.5° → 2.6, 30° → 2.0, 45° → 1.4, 60° → 1.15. ESTIMATE ONLY — final layout must be verified against the actual bender deduct/take-up and AHJ requirements. Bend radius and fill rules come from NEC Article 358 for EMT (and parallel articles for IMC, RMC, ENT).
How to use this calculator
Pick offset (2 bends to step a conduit around an obstruction) or 3-bend saddle (3 bends to clear an obstacle in the middle of a run). Enter the rise in inches — for offsets, this is the height the conduit needs to step; for saddles, this is the height of the obstacle.
Pick the bend angle: 22.5° and 30° are common low-angle offsets that minimize shrink and pull friction; 45° is the steepest most benders go without binding wire on the pull. The calculator returns the distance between bends (offset) or center-to-side bend distance (saddle) plus the shrink — the amount the conduit run loses to the bend curvature. Add shrink to your start mark so the run lands where it needs to.
Worked example
For a 4-inch offset at 30° in EMT:
Multiplier (30°): 2.0. Distance between bends: 4 × 2.0 = 8 inches between marks. Shrink: 4 × 0.25 = 1 inch — add 1 inch to your start mark so the run lands correctly after the offset.
For the same 4-inch offset at 22.5°:
Multiplier: 2.6. Distance: 4 × 2.6 = 10.4 inches. Shrink: 4 × 0.1875 = 0.75 inch. The shallower angle has a longer offset (less compact) but less shrink.
For a 3-bend saddle clearing a 6-inch obstacle with a 45° centre bend:
The side bends are 22.5°, so the layout multiplier is 2.6 — the one for the SIDE angle, not the centre. Center-to-side bend: 6 × 2.6 = 15.6 inches. Total shrink: 2 × (6 × 0.1875) = 2.25 inches.
Mark center → measure 15.6 inches each direction for side bends → bend center at 45°, side bends at 22.5° each. Laying this out with the 45° multiplier instead gives 8.4 inches and the saddle will not clear the obstacle.
Common mistakes & waste factors
Forgetting the shrink. Bends compress the conduit run length. A 4-inch offset at 30° loses 1 inch of run to the bend curvature. Failing to add shrink to your start mark means the conduit lands 1 inch short of the box.
Using the offset multiplier on a saddle. Saddles use the same multipliers but in a different geometric pattern (3 bends, not 2). The center bend is at the angle; side bends are at half the angle.
Maxing out at 45°. Offsets above 45° compress the wire bundle and make pulling difficult. For deep offsets, consider a longer 30° offset over multiple steps.
Ignoring the bender deduct. Every bender has a take-up or deduct value (the distance from the start mark to the center of the bend). The calculator gives geometric numbers; subtract the bender deduct from your first mark to get the actual measurement.
Rules of thumb
Multipliers: 22.5° → 2.6, 30° → 2.0, 45° → 1.4, 60° → 1.15.
Shrink per inch of rise: 22.5° → 3/16", 30° → 1/4", 45° → 3/8", 60° → 1/2".
Low-angle offsets (22.5°/30°) minimize pull friction; high-angle (45°/60°) keep the bend compact but bind wires on pull.
Saddle: centre bend at the angle, side bends at half the angle — and the layout multiplier is the one for the SIDE angle. A 45° centre saddle lays out with the 22.5° multiplier (2.6), a 60° centre with the 30° multiplier (2.0). This is the most common saddle mistake.
Always subtract bender deduct/take-up from your first mark — the calculator gives the geometric distance between bend centers.
Common questions
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