Bending Reference
Conduit Shrink Calculator
The shrinkage chart for every standard bend angle, applied to offsets, kicks, and saddles. Shrink depends on the angle and the height, not the conduit size, so one chart covers 1/2 inch through 1-1/4 inch EMT. Interactive calculator, worked examples, and the formula.
Conduit Shrinkage Chart
Shrink per inch of offset or kick height by bend angle. The multiplier column is the mark spacing factor (1 / sin of the angle) for the same bend, included so you can lay out the whole offset from one table.
| Bend Angle | Shrink per Inch | Shrink (decimal) | Multiplier |
|---|---|---|---|
| 10° | 1/16" | 0.063 | 5.76 |
| 15° | 1/8" | 0.125 | 3.86 |
| 22.5° | 3/16" | 0.188 | 2.61 |
| 30° | 1/4" | 0.250 | 2.00 |
| 45° | 3/8" | 0.375 | 1.41 |
| 60° | 1/2" | 0.500 | 1.15 |
For any angle not listed, shrink per inch = tan(angle / 2). These are the same constants the calculator below uses.
Total Shrink by Offset or Kick Height
Pre-computed total shrink (height × the constant above) for the three most common field angles. Read down to your offset height or kick rise and subtract the value from your first mark.
| Height | Shrink @ 22.5° | Shrink @ 30° | Shrink @ 45° |
|---|---|---|---|
| 2" | 3/8" | 1/2" | 3/4" |
| 3" | 9/16" | 3/4" | 1-1/8" |
| 4" | 3/4" | 1" | 1-1/2" |
| 5" | 15/16" | 1-1/4" | 1-7/8" |
| 6" | 1-1/8" | 1-1/2" | 2-1/4" |
| 8" | 1-1/2" | 2" | 3" |
| 10" | 1-7/8" | 2-1/2" | 3-3/4" |
Calculate Shrink for Your Bend
Enter your offset height and angle to get exact shrink, travel, and marks with a diagram. Switch the bend type to kick-90 to get shrink per inch of kick, or to a saddle for the three- and four-point shrink.
Shrink by Bend Type
Offset shrink
An offset is two equal bends. Total shrink is the offset height times the shrink-per-inch constant for the angle. A 4 inch offset at 30 degrees shrinks 4 × 1/4" = 1". Subtract that from the distance to your first mark so the far leg lands where the straight run is supposed to resume.
Kick shrink
A kick is one bend that lifts the stub off the straight line. Shrink per inch of kick height is identical to the offset constant, because the geometry of the single bend is the same. Kick a stub up 3 inches at 30 degrees and the pipe shortens 3 × 1/4" = 3/4", so take 3/4" off the stub height when you measure. The dedicated kick 90 calculator places both the 90 and the kick mark together.
Saddle shrink
A three-point saddle is a center bend with two outer bends at half that angle, so its shrink is keyed to the outer angle and the saddle depth. A four-point saddle is two opposing offsets, so its shrink is roughly double a single offset of the same depth. The saddle bend calculator works out the exact spacing and shrink for both.
Does Conduit Size Change the Shrink?
No. This is the single most common shrink question, and the answer is that shrink is a function of the bend angle and the height of the offset or kick, not the diameter of the pipe. A 30 degree offset shrinks 1/4 inch per inch of height on 1/2 inch EMT, on 3/4 inch EMT, and on 1 inch EMT alike. There is no separate "3/4 EMT shrinkage" number.
What does change with conduit size is the take-up (deduct) on a 90 degree stub: 5 inches for 1/2 inch, 6 inches for 3/4 inch, 8 inches for 1 inch, and 11 inches for 1-1/4 inch EMT on a standard hand bender. That is a different measurement from shrink, and it is easy to mix the two up because both shorten the pipe. Use the 90 degree deduction chart for take-up by size, and this page for offset and kick shrink by angle.
Worked Example: 6-Inch Offset at 30 Degrees
Given: A beam forces the run up 6 inches. The point where the offset must finish is 48 inches from the end of your conduit. You bend at 30 degrees for easy math.
Step 1: Shrink. Shrink = 6 × 1/4" = 1-1/2 inch. The run will be 1-1/2 inch shorter after both bends.
Step 2: First mark. 48 − 1-1/2 = 46-1/2 inches to the first bend mark, so the far leg still lands at 48 inches after the pipe pulls in.
Step 3: Second mark. Travel = 6 × 2.00 (the 30 degree multiplier) = 12 inches. Second mark at 46-1/2 + 12 = 58-1/2 inches.
Result: Bend 30 degrees at each mark in the same plane. The 6 inch rise clears the beam and the run resumes exactly at 48 inches because you took out the shrink.
Frequently Asked Questions
How much does conduit shrink per inch of offset?
Shrink per inch of offset height is 1/16 inch at 10 degrees, 1/8 inch at 15 degrees, 3/16 inch at 22.5 degrees, 1/4 inch at 30 degrees, 3/8 inch at 45 degrees, and 1/2 inch at 60 degrees. Multiply that constant by the offset height to get total shrink. A 4 inch offset at 30 degrees shrinks 4 x 1/4 = 1 inch.
How much shrink per inch of kick?
A kick is a single bend, so shrink per inch of kick height uses the same constants as an offset: 1/4 inch of shrink per inch of kick at 30 degrees, 3/16 inch at 22.5 degrees, and 3/8 inch at 45 degrees. If you kick a stub up 3 inches at 30 degrees, the conduit gets 3 x 1/4 = 3/4 inch shorter, so shorten your stub measurement by 3/4 inch.
Does conduit shrink depend on the pipe size?
No. Shrink depends only on the bend angle and the offset or kick height, not on the conduit size. A 30 degree offset shrinks 1/4 inch per inch of height whether you are bending 1/2 inch, 3/4 inch, or 1 inch EMT. What changes with conduit size is take-up on a 90 degree bend (the deduct), not offset or kick shrink. That is why one shrink chart covers every size.
What is the shrink for 3/4 EMT?
The same as any other size. There is no separate 3/4 inch EMT shrink value: at 30 degrees it is 1/4 inch per inch of offset height, at 45 degrees 3/8 inch per inch, regardless of pipe diameter. If you were looking for the 90 degree deduction for 3/4 inch EMT, that is 6 inches (take-up), which is a different number that does vary by size.
Why does bending conduit make the run shorter?
When you put a bend in conduit, the pipe follows the hypotenuse of a triangle instead of running straight and then square, so the two ends pull closer together. That lost distance is shrink. The steeper the angle, the more the pipe rises over a shorter travel, so the more it shrinks per inch of height. You compensate by subtracting the shrink from the distance to your first bend mark.
How do I use shrink to place my first bend mark?
Measure from a fixed reference (a box, a wall, the end of the pipe) to where the obstruction or the far side of the offset needs to land, then subtract the total shrink. Example: the offset needs to clear a pipe 40 inches away, and you are bending a 5 inch offset at 30 degrees. Shrink = 5 x 1/4 = 1-1/4 inch, so your first mark goes at 40 - 1-1/4 = 38-3/4 inches.
Where does the shrink constant come from?
Shrink per inch equals tan(angle / 2). For a 30 degree bend, tan(15 degrees) = 0.268, which the trade rounds to 1/4 inch. For 45 degrees, tan(22.5 degrees) = 0.414, rounded to 3/8 inch. The multiplier that spaces the marks is the cosecant, 1 / sin(angle). Both come straight from the geometry of the bend, which is why they are the same on every conduit size.
More Bending References
Conduit Bending Calculator
All 7 bend types with interactive SVG diagrams and verified bender profiles.
Offset Multiplier Chart
Multipliers and travel for 10 to 60 degree offsets, with worked examples.
Kick 90 Calculator
Kick marks, travel, and shrink per inch of kick for stub-and-kick combos.
90° Deduction Chart
Take-up, deduct, radius, and gain for 1/2" through 1-1/4" EMT by size.
Saddle Bend Calculator
3-point and 4-point saddle marks, spacing multipliers, and shrink.