Bending Reference
EMT Offset Multiplier Chart
Multipliers and shrink constants for every standard offset angle: 10, 15, 22.5, 30, 45, and 60 degrees. Travel tables for common offset heights, worked examples, and the formula for any angle in between.
Offset Multiplier and Shrink Chart
Travel (distance between marks) = offset height × multiplier. Shrink = offset height × shrink per inch. The multiplier is 1 / sin(angle); the shrink constants are the trade-standard fractions used on bender shoes and in apprenticeship texts.
| Bend Angle | Multiplier | Shrink per Inch | Shrink (decimal) |
|---|---|---|---|
| 10° | 5.76 | 1/16" | 0.063 |
| 15° | 3.86 | 1/8" | 0.125 |
| 22.5° | 2.61 | 3/16" | 0.188 |
| 30° | 2.00 | 1/4" | 0.250 |
| 45° | 1.41 | 3/8" | 0.375 |
| 60° | 1.15 | 1/2" | 0.500 |
For any angle not listed, compute the multiplier as 1 / sin(angle) and shrink per inch as tan(angle / 2). These are the same formulas the calculator below uses.
Travel and Shrink for Common Offset Heights
Pre-computed mark spacing (travel) and total shrink for the two most common field angles. Values are calculated with travel = height / sin(angle) and shrink = height × the constant from the chart above.
| Offset Height | Travel @ 30° | Shrink @ 30° | Travel @ 45° | Shrink @ 45° |
|---|---|---|---|---|
| 2" | 4" | 1/2" | 2.83" | 3/4" |
| 3" | 6" | 3/4" | 4.24" | 1-1/8" |
| 4" | 8" | 1" | 5.66" | 1-1/2" |
| 5" | 10" | 1-1/4" | 7.07" | 1-7/8" |
| 6" | 12" | 1-1/2" | 8.49" | 2-1/4" |
| 8" | 16" | 2" | 11.31" | 3" |
Calculate Any Offset
Enter your offset height and angle to get exact marks, travel, and shrink with an SVG diagram. The calculator also handles rolling offsets, saddles, 90s, and kicks.
Worked Example: 5-Inch Offset at 22.5 Degrees
Given: A duct forces your run up 5 inches, and the obstruction starts 36 inches from the end of the conduit. You choose 22.5 degrees because your bender head has a dedicated 22.5 degree mark.
Step 1: Travel. Travel = 5 × 2.61 = 13.07 inches between marks (exactly 5 / sin(22.5°)).
Step 2: Shrink. Shrink = 5 × 3/16" = 15/16 inch. The run gets almost an inch shorter, so measure to the obstruction and subtract: 36 − 15/16 = 35-1/16 inches to the first mark.
Step 3: Mark and bend. First mark at 35-1/16", second mark 13.07" farther along. Bend 22.5 degrees at the first mark, flip the conduit, sight the bends in the same plane, and bend 22.5 degrees at the second mark.
Result: A 5-inch rise over about 13 inches of run, with the far side of the offset landing exactly where the straight run resumes.
Frequently Asked Questions
What is the multiplier for a 10 degree bend?
The multiplier for a 10 degree offset is 5.76 (1 divided by sin(10 degrees)). Many electricians round it to 6 for quick field math. Shrink is 1/16 inch per inch of offset height. A 10 degree offset needs a lot of room: a 4-inch offset requires about 23 inches of travel between marks, so use it only where you have long straight runs and want the gentlest possible wire pull.
What is the 22.5 degree offset multiplier?
The multiplier for a 22.5 degree offset is 2.61, and the shrink is 3/16 inch per inch of offset height. For a 4-inch offset at 22.5 degrees, the marks are 4 x 2.61 = 10.45 inches apart and the run shrinks 4 x 3/16 = 3/4 inch. The 22.5 degree angle is popular because most bender heads have a dedicated 22.5 degree mark.
What is the multiplier for a 30 degree offset?
The multiplier for a 30 degree offset is exactly 2.00, because sin(30 degrees) = 0.5. Multiply the offset height by 2 to get the distance between your two bend marks, and use 1/4 inch of shrink per inch of offset height. This easy math is why 30 degrees is the standard angle taught in apprenticeship programs.
How do you find the offset multiplier for any angle?
Multiplier = 1 / sin(bend angle). That is the cosecant of the angle. For example, 1 / sin(45 degrees) = 1 / 0.7071 = 1.41. Shrink per inch for any angle equals tan(angle / 2), which is where the trade constants come from: tan(15 degrees) = 0.268, rounded to the field value of 1/4 inch for a 30 degree bend. The chart on this page covers every standard hand bender angle so you rarely need the formula on the job.
How do I use shrink when laying out an offset?
Shrink is how much shorter the conduit run becomes after you bend the offset. Multiply the offset height by the shrink-per-inch constant for your angle, then subtract that amount when measuring to your first mark from a fixed reference point. Example: your obstruction is 30 inches away and you are bending a 4-inch offset at 30 degrees. Shrink = 4 x 1/4 inch = 1 inch, so your first mark goes at 30 - 1 = 29 inches.
Does conduit size change the offset multiplier?
No. The multiplier and shrink constants depend only on the bend angle, not the conduit size. A 30 degree offset uses a multiplier of 2.00 whether you are bending 1/2 inch or 1-1/4 inch EMT. Conduit size matters for 90 degree bends, where take-up, gain, and deduct change with the bender shoe. See the 90 degree deduction chart for those values.
How many degrees does an offset add toward the NEC 360 degree limit?
An offset counts as twice its bend angle, because it is two equal bends. A 30 degree offset adds 60 degrees; a 45 degree offset adds 90 degrees. NEC 358.26 limits EMT runs to 360 degrees of total bends between pull points, so a run with two 90s (180 degrees) and two 30 degree offsets (120 degrees) is at 300 degrees and has room for only one more small offset before it needs a pull box.
More Bending References
Conduit Bending Calculator
All 7 bend types with interactive SVG diagrams and verified bender profiles.
90° Deduction Chart
Take-up, deduct, radius, and gain for 1/2" through 1-1/4" EMT.
Kick 90 Calculator
Kick marks, travel, and shrink per inch of kick for stub-and-kick combos.
Saddle Bend Calculator
3-point and 4-point saddle marks, spacing multipliers, and shrink.
Conduit Fill Calculator
Check NEC Chapter 9 fill compliance for any conduit and conductor combination.