Conduit offset multiplier and shrink chart
Multiply the offset height by the multiplier to get the distance between bends. Multiply it by the shrink per inch to get how much shorter the run gets.
| Angle | Multiplier | Rule of thumb | Shrink per inch | Rule of thumb |
|---|---|---|---|---|
| 5° | 11.474 | 11.5 | 0.044 | 1/32" |
| 10° | 5.759 | 6 | 0.087 | 1/16" |
| 15° | 3.864 | 3.9 | 0.132 | 1/8" |
| 22.5° | 2.613 | 2.6 | 0.199 | 3/16" |
| 30° | 2.000 | 2 | 0.268 | 1/4" |
| 45° | 1.414 | 1.4 | 0.414 | 3/8" |
| 60° | 1.155 | 1.2 | 0.577 | 1/2" |
How to use the chart
- Measure the offset height: how far the conduit has to move, center to center.
- Pick an angle. 30° is the usual choice; 45° for a tall offset in a tight space; 10° or 22.5° for a small one.
- Distance between bends = offset height × multiplier.
- Shrink = offset height × shrink per inch. Add it to the distance to the obstruction when you measure from the end.
Example: A 6" offset at 30°: 6 × 2 = 12" between bends, and 6 × 0.268 = 1.61", about 1 5/8", of shrink.
Distance between bends for common offsets
| Offset height | 10° | 22.5° | 30° | 45° | 60° |
|---|---|---|---|---|---|
| 1" | 5 3/4" | 2 5/8" | 2" | 1 7/16" | 1 1/8" |
| 2" | 11 1/2" | 5 1/4" | 4" | 2 13/16" | 2 5/16" |
| 3" | 17 1/4" | 7 13/16" | 6" | 4 1/4" | 3 7/16" |
| 4" | 23 1/16" | 10 7/16" | 8" | 5 11/16" | 4 5/8" |
| 5" | 28 13/16" | 13 1/16" | 10" | 7 1/16" | 5 3/4" |
| 6" | 34 9/16" | 15 11/16" | 12" | 8 1/2" | 6 15/16" |
| 8" | 46 1/16" | 20 7/8" | 16" | 11 5/16" | 9 1/4" |
| 10" | 57 9/16" | 26 1/8" | 20" | 14 1/8" | 11 9/16" |
| 12" | 69 1/8" | 31 3/8" | 24" | 17" | 13 7/8" |
Why BendMate’s numbers are a little smaller
The chart treats each bend as a sharp corner. A real shoe bends on a radius, which cuts the corner and uses a little less conduit. BendMate works that out from your bender’s centerline radius, so its distance between bends and shrink come out slightly smaller than the chart’s, and match what the shoe does.
Common questions
What is the multiplier for a 10° offset?
5.76, often rounded to 6. Multiply the offset height by it to get the distance between the bends. The shrink is 0.087" per inch of offset height, about 1/16".
What is the multiplier for a 22.5° offset?
2.61, often rounded to 2.6. Multiply the offset height by it to get the distance between the bends. The shrink is 0.199" per inch of offset height, about 3/16".
What is the multiplier for a 30° offset?
2. Multiply the offset height by it to get the distance between the bends. The shrink is 0.268" per inch of offset height, about 1/4".
What is the multiplier for a 45° offset?
1.41, often rounded to 1.4. Multiply the offset height by it to get the distance between the bends. The shrink is 0.414" per inch of offset height, about 3/8".
What is the multiplier for a 60° offset?
1.15, often rounded to 1.2. Multiply the offset height by it to get the distance between the bends. The shrink is 0.577" per inch of offset height, about 1/2".
Get the marks for your bender
BendMate works this out from your bender’s radius and deduct, flags a bend that won’t work, and shows you every mark.