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Conduit bending multipliers and shrink
Offset multipliers and shrink per inch of offset for the common bend angles, worked out with the same math as the conduit bending calculator. Multiply the offset height by the multiplier for the distance between marks, and by the shrink for how much shorter the run gets.
Also here: typical 90° take-up for EMT hand benders (check the number printed on yours) and the three-point saddle rule of thumb.
Verify with your local code and AHJ. Reference only, no warranty.
Offsets
| Multiplier | Shrink/in | ≈ | |
|---|---|---|---|
| 10° | 5.76 | 0.087 | 1/16″ |
| 22 1/2° | 2.61 | 0.199 | 3/16″ |
| 30° | 2.00 | 0.268 | 1/4″ |
| 45° | 1.41 | 0.414 | 7/16″ |
| 60° | 1.15 | 0.577 | 9/16″ |
Marks apart = offset × multiplier. Shrink = offset × shrink per inch.
90° take-up, typical EMT bender
| 1″ EMT | 8″ |
| 1/2″ EMT | 5″ |
| 3/4″ EMT | 6″ |
| 1 1/4″ EMT | 11″ |
Check the number printed on your bender.
Three-point saddle
| Center bend | 45° |
| Outer bends | 22 1/2° |
| Outer marks from center | 2 1/2 × height |
| Move center mark | 3/16″ per inch of height |
Open this sheet in the toolkit to search it, pin it and use it offline.
Questions
What is the multiplier for a 45° offset?
1.41. Shrink is 0.414 per inch of offset.
What is the shrink for a 30° offset?
0.268 per inch, about 1/4″ — the pocket-chart figure.
What is the take-up for 3/4″ EMT?
Typically 6″ on a hand bender. Check the number printed on yours.