Every offset bend starts with one number: the multiplier. It converts the height of your offset into the distance between your two bend marks. Get the multiplier right and the offset lands exactly where the box is; get it wrong and nothing lines up.
The multiplier is the cosecant of the bend angle — 1 divided by the sine. You do not need to do the trigonometry on the job: the table below covers every angle a hand bender makes. Find your angle, multiply the offset height by the number in the table, and that is the distance between your marks.
| Bend angle | Multiplier | Shrink per inch of offset |
|---|---|---|
| 10° | 6.0 | 1/16" |
| 15° | 3.9 | 1/8" |
| 22.5° | 2.6 | 3/16" |
| 30° | 2.0 | 1/4" |
| 45° | 1.4 | 3/8" |
| 60° | 1.2 | 1/2" |
Say you need a 4" offset and you are bending 30° kicks. The multiplier for 30° is 2.0, so your marks go 4 × 2.0 = 8" apart. Make the first bend on the first mark, flip the bender, and make the second bend on the second mark in the opposite direction. The conduit shifts 4" and keeps running parallel.
Do not forget the third column: the bend also eats conduit. That same 4" offset at 30° shrinks the run by 4 × 1/4" = 1". If the conduit has to land on a coupling or a box at an exact point, add that inch back when you measure.
Thirty degrees is the default offset angle for a reason: the multiplier is exactly 2.0, so the math is doubling — no chart needed. The shrink is a manageable 1/4" per inch, and the bend is shallow enough to pull wire through easily. Save the 45° and 60° kicks for when space is tight.
Exactly 2.0. A 6-inch offset at 30 degrees needs 12 inches between bend marks — just double the height.
The multiplier is 1 divided by the sine of the angle. For odd angles, skip the hand math: the free offset calculator gives you mark spacing and shrink directly.
No. The multiplier is pure geometry — it depends only on the bend angle, not the material. What changes between EMT and rigid is take-up and springback, not the multiplier.
The multiplier sets the distance between your bend marks. Shrink is the conduit length the bend consumes along the run. You need both: multiplier to place the marks, shrink to cut the pipe to the right length.
Try it free: Open the free offset bend calculator — all six bend calculators, no sign-up.
Get Conduit Bend Calc on Google Play for bender calibration and Pro tools.