Conduit Bending Calculator
Work out offset, three-point saddle and 90° stub marks for EMT conduit: distance between marks, shrink and the deduct, from the height and the bend angle. Uses the multipliers, shrink and deducts printed in a hand bender guide, with the exact trig figures next to them.
Your numbers
The chart is what the bender guide prints; the table under the result shows both.
How far the conduit has to move up or over. Decimals: 3.5 for 3-1/2.
Optional: gives both marks measured from the end of the conduit.
Distance between marks
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- Multiplier at 30°
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- Shrink
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Offset multipliers and shrink
The bender chart columns are from the Gardner Bender 960 series guide; the trig columns are 1 ÷ sin θ and tan(θ ÷ 2), the sharp-corner figures the chart rounds.
| Angle | Multiplier (chart) | Multiplier (trig) | Shrink per inch (chart) | Shrink per inch (trig) |
|---|---|---|---|---|
| 10° | 6.0 | 5.759 | 1/16 in | 0.087 in |
| 22½° | 2.6 | 2.613 | 3/16 in | 0.199 in |
| 30° | 2.0 | 2 | 1/4 in | 0.268 in |
| 45° | 1.4 | 1.414 | 3/8 in | 0.414 in |
| 60° | 1.2 | 1.155 | 1/2 in | 0.577 in |
How the offset marks are worked out
An offset is two equal bends in opposite directions that move the conduit up or over by the offset height. The distance between the two marks is the height × the multiplier for the angle, and the conduit gets shorter along the run by the shrink, the height × the shrink per inch. Shallow angles need more room between the marks but shrink less; steep ones fit a short space but are harder to pull wire through.
Working toward an obstacle, measure from the end of the conduit to the obstacle and add the shrink: that is the mark nearest the obstacle. Subtract the distance between the marks for the second mark, nearer the end. Line both marks up with the arrow and bend the second one in the opposite direction, rolling the conduit half a turn.
Worked example: a 10 inch offset at 45°, 30 inches from the end of the conduit to the obstacle. The chart multiplier is 1.4, so the marks are 10 × 1.4 = 14 inches apart; the shrink is 10 × 3/8 = 3-3/4 inches. The first mark goes at 30 + 3-3/4 = 33-3/4 inches and the second at 33-3/4 − 14 = 19-3/4 inches from the end.
Three-point saddles over a pipe
A three-point saddle crosses a round obstacle with a 45° bend in the middle and a 22½° bend each side. The Gardner Bender guide moves the centre mark 3/16 inch ahead for each inch of obstacle height and puts the outer marks 2½ times the height either side of the centre. Bend the centre on the rim notch first, then each outer mark on the arrow.
In trig terms the saddle is two 22½° offsets back to back: the outer marks sit the height ÷ sin 22½° = 2.61 times the height from the centre, and the conduit shrinks 0.199 inch per inch of height on the way to the centre. The chart rounds these to 2½ and 3/16. Another method, a 60° centre with two 30° outer bends, is in the same guide without a chart; this calculator does the 45° saddle only.
90° stub-ups and the deduct
For a stub-up, the bend takes up some of the length, so the mark goes the deduct short of the stub height: 5 inches on ½ inch EMT, 6 inches on ¾ inch and 8 inches on 1 inch on the common hand benders. Line the mark up with the arrow, keep foot pressure on the bender and bend to 90°. The back of the bend then sits at the stub height.
Check your bender
Benders from different makers, and different models from one maker, have different marks, deducts and radii. The figures here are from the Gardner Bender 960 series guide, and other guides differ: Elliott Electric's EMT instructions place the saddle's outer marks at twice the pipe's diameter. Use the numbers stamped on your bender when they differ, and bend a scrap piece before the one that matters.
For electrical distributor reps: what to write down on the job walk
The bending is the electrician's call; the order is yours. Note the conduit sizes and runs, what the runs cross, whether the contractor needs a bender or a spare head in that size, and the date the job starts. Write it down while you are on site and read it back before you send the quote.
Sources, each read on 2026-10-28. Check the marks on your own bender:
- Gardner Bender: Benfield Style Hand Bender, How to Bend Guide, 960 Series (offset multipliers and shrink, saddle marks, EMT deducts)
- Elliott Electric Supply: Conduit Bending Instructions (EMT Bender) (take-up by size, saddle method)
Sizing the run as well? The conduit fill calculator checks how many wires fit, and the voltage drop calculator checks the wire size over the length.
More for electrical contractors and distributor reps: Electrical distributor sales, Construction daily report, Distributor sales.
The runs get walked before they get bent
Where the conduit goes, what is in the way and what the customer asked for all come up on the job walk. Record it in ParrotNotes and get a structured note, a summary and the action items, so the runs and the obstacles are in the notes when you price the job. Free for 100 minutes of recording a month.
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