Bending Calculator
Parallel Offset Calculator
Marks for two to six conduits bent side by side so they stay parallel through the bend: parallel offsets, parallel kicks (sideways and forward), and matching bends or matching centers across two EMT sizes. Every conduit is checked against its own bend radius.
One Rule, Five Bends
Two parallel conduits spaced S apart in the plane of a bend, both turning t degrees, stay S apart after the bend only if their bend corners sit S × tan(t ÷ 2) apart along the pipe, the conduit on the inside of the turn having its corner that much closer to the end the marks are measured from. The marks this calculator lays out are laid at the sharp-corner spacing the bender charts use, so the mark is the corner: what moves the corner moves the mark by the same amount, on any size. An offset turns twice in opposite directions and the two shifts point the same way along the pipe, so both marks move together and the travel is unchanged. Two conduits also cannot sit closer than their outside diameters, so the spacing is floored there. None of the bender manuals this site holds describes these bends, so the definitions below are the geometry the calculator implements, stated in words.
- Parallel offset: two to six conduits of one size, stacked in the direction the offset rises. Each conduit toward the rise moves both marks one shift closer to the flush end.
- Parallel kick, sideways: a rack of stubs kicked across the rack's own plane. The 90 marks are identical; each conduit toward the kick side moves its kick mark one shift toward the stub end, so the innermost conduit has the least room between its 90 and its kick and is the one checked first.
- Parallel kick, forward: the same rack kicked in the plane of the 90, up or down. The conduits stand across the kick plane, so every one takes the same two marks and the shift is zero, stated rather than invented.
- Matching bends: two conduits of different sizes run parallel through one offset. Conduit 2's marks move one shift toward the flush end, exactly as in a parallel offset, so the two bends sit on one line across the rack and the spacing holds on the straights. Through the bends two different radii close on each other a little; the calculator prints the closest the two centerlines come and refuses the pair when that is inside the two outside diameters. Each size is checked against its own bend radius.
- Matching centers: the same pair with no shift: the same two marks on both conduits, so both offsets center on one station along the run. Through the angled leg the two close up to the spacing times the cosine of the angle and open back out after it; the calculator prints that closer figure and refuses the pair when it is inside the two outside diameters. A bend center here means the point on the run the offset is centered on, not the center mark of a saddle and not the conduit's centerline.
Mark Shift by Bend Angle
The shift per inch of center-to-center spacing is tan(angle ÷ 2). It is the same on every conduit size and for every bender, because it comes from the angle alone. Multiply by your spacing, or read the 2" and 4" columns.
| Bend Angle | Shift per Inch of Spacing | 2" Spacing | 4" Spacing |
|---|---|---|---|
| 10° | 0.087 | 0.17" | 0.35" |
| 15° | 0.132 | 0.26" | 0.53" |
| 22.5° | 0.199 | 0.4" | 0.8" |
| 30° | 0.268 | 0.54" | 1.07" |
| 45° | 0.414 | 0.83" | 1.66" |
| 60° | 0.577 | 1.15" | 2.31" |
Worked Example: Three 1/2" Conduits, 2" Apart, 4" Offset at 30°
Given: a rack of three 1/2" EMT conduits on 2" centers has to jog up 4 inches. You choose 30 degrees. Hold all three flush at one end and measure every mark from it.
Step 1: Travel. 4 × 2.0 = 8" between the two marks, the same on every conduit.
Step 2: Shift. 2 × tan(15°) = 2 × 0.268 = 0.54" per conduit.
Step 3: The marks. Conduit 1 (outside of the first bend): 1.07" and 9.07"; Conduit 2 (middle): 0.54" and 8.54"; Conduit 3 (toward the rise): at the flush end and 8".
Result: three offsets 2" apart before, through and after the bend, each conduit's marks 0.54" closer to the flush end than the one below it.
Matching Across Two Sizes: 1/2" Beside Each EMT Size, 2" Apart at 30°
Conduit 1 is 1/2" EMT on the outside of the first bend; conduit 2 is the size in each row, 2" toward the rise, through a 4" offset at 30°. The first row is the same size on both sides, where the two families must agree at rest. Matching bends shifts conduit 2 and holds the spacing on the straights; through the bends two different radii still close on each other a little, and the calculator prints the closest the two centerlines come and refuses when that is inside the two outside diameters. Matching centers shifts nothing and the pair closes up through the offset to the figure in the last column. The floor is the closest the two sizes can sit center to center.
| Conduit 2 | Closest Centers Can Sit | Matching Bends: Shift | Matching Bends: On the Straights | Matching Bends: Closest Through the Bends | Matching Centers: Through the Offset |
|---|---|---|---|---|---|
| 1/2" EMT | 0.71" | 0.54" | 2" | 2" | 1.73" |
| 3/4" EMT | 0.81" | 0.54" | 2" | 2" | 1.73" |
| 1" EMT | 0.93" | 0.54" | 2" | 2" | 1.73" |
| 1-1/4" EMT | 1.11" | 0.54" | 2" | 1.96" | 1.73" |
Where a Sideways Parallel Kick Runs Out of Room
A 24" stub with a 5" kick at 30° in 1/2" EMT, conduits 2" apart, kicked sideways across the rack. Each conduit toward the kick side has its kick mark 0.54" closer to its 90 mark; past its arrow the 90 consumes the take-up less half the OD, minus the 4" radius of straight, and then the quarter arc, and the 30° arc needs its own lead-in, so the run between the marks must hold both. Every row is run through the calculator; a refused row prints the calculator's own sentence.
| Conduits | Innermost Run, 90 to Kick |
|---|---|
| 2 | 9.46" |
| 3 | 8.93" |
| 4 | 8.39" |
| 5 | not bendable in 1/2" EMT (smallest kick height that works: 5-1/8") |
| 6 | not bendable in 1/2" EMT (smallest kick height that works: 5-3/8") |
Frequently Asked Questions
What is the parallel offset formula?
Mark shift = center-to-center spacing x tan(bend angle / 2). At 30 degrees that is 0.268 inch per inch of spacing, so two conduits 2 inches apart shift 0.54 inch; at 45 degrees it is 0.414 per inch. Both marks on each successive conduit move by the same amount toward the end you measure from, and the distance between the two marks (the travel) does not change. It comes straight from the geometry of two parallel lines turning the same angle, which is why it is the same on every conduit size and every bender.
Which conduit's marks move, and which way?
Hold every conduit flush at one end and measure all the marks from it. The conduit on the outside of the first bend (the side the offset rises away from) keeps the longest marks; each conduit toward the rise, the inside of that first bend, has both marks moved the shift closer to the flush end. If you are stacking three conduits, the middle one moves one shift and the inside one moves two.
Do conduits side by side need the shift?
Only if the spacing is in the plane of the bend. Conduits lying flat on a wall and offsetting away from the wall are side by side across the bend plane: geometrically they are one pipe, every one takes the same marks, and no shift applies. Conduits stacked in the direction the offset rises are in the bend plane and need the shift. The same rule sorts the two parallel kicks: a sideways kick across a rack shifts the kick marks, a forward kick in the plane of the 90 does not.
What is the difference between matching bends and matching centers?
They are the two ways this calculator lays two different sizes through one offset, and it states both as its own definitions. Matching bends runs them parallel: conduit 2's marks move spacing x tan of half the angle toward the flush end, the same shift as a parallel offset of one size, and the spacing holds through the offset. Matching centers puts the same two marks on both conduits so both offsets center on one station; through the angled leg the two close up to the spacing times the cosine of the angle and open back out after it, and the calculator refuses the pair when that closer figure is inside the two outside diameters. With 1/2 inch and 1-1/4 inch EMT 2 inches apart at 30 degrees, matching bends shifts conduit 2 by 0.54 inch and holds 2 inches through the offset; matching centers holds 1.73 inches there. Each size is checked against its own NEC Chapter 9, Table 2 bend radius either way.
Why does a parallel kick refuse a rack that a single kick could make?
Each conduit toward the kick side has its kick mark moved the shift closer to its 90 mark, so the innermost conduit has the shortest run between its two bends. Past its arrow the finished 90 consumes the take-up less half an OD, minus the radius of straight, and then the quarter arc at the NEC Chapter 9 Table 2 bend radius, and the kick arc needs its own lead-in, so the run between the two marks must hold both; when the innermost conduit runs out of it the calculator refuses the whole rack and names the smallest kick height that works for that rack. With 24 inch stubs, a 5 inch kick at 30 degrees and 2 inch spacing in 1/2 inch EMT, a rack of 2 or 3 or 4 conduits bends and racks of 5, 6 refuse.
Where do these definitions come from?
From geometry, stated on this page. None of the bender manuals this site holds (Greenlee, Gardner Bender, Klein) describes parallel or matching bends, so there is no table to cite and no rounding to inherit: the shift is the tangent of half the angle times the spacing, the radii are the NEC Chapter 9 Table 2 one-shot values, and the travel is the same offset multiplier the offset calculator applies. Whether a bend can be made is checked for every conduit at its own size.
More Bending References
Conduit Bending Calculator
Every bend type as an interactive 3D rendering or flat diagram, with verified bender profiles.
Offset Multiplier Chart
Multipliers and shrink per inch for 10° through 60° offset bends.
Kick 90 Calculator
Kick marks, travel, and shrink per inch of kick by angle.
90° Deduction Chart
Take-up, deduct, radius, and gain for 1/2" through 1-1/4" EMT.
Printable Cheat Sheet
Every bending constant on one page. Print, save the PDF, or download the image for your phone.
Conduit Fill Calculator
Check NEC Chapter 9 fill compliance for any conduit and conductor combination.
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Connect Intry to Claude once, then just say “use Intry to…” to run the parallel and matching bend calculator from a plain-English question, on your phone, on the job. You get the number (computed live, not guessed), what it means, and the bender chart or geometry it was computed from and the NEC Chapter 9 Table 2 radius. Works on every Claude plan.