Conduit Bending Calculator

What this calculator does

Find exactly where to put your marks before you bend conduit, for offsets, stub-ups, back-to-back bends and saddles. With a hand bender, most of the job is getting the marks right. An offset (a jog around something) needs two marks a set distance apart. A stub-up (a 90° bend that turns the pipe up) needs its mark pulled back by the bender's take-up. A saddle over a pipe needs three marks centered on the obstacle. Each of those distances comes from a little trigonometry, the math of triangles. Electricians usually carry it around as a table of multipliers and shrink amounts.

This conduit bending calculator works the numbers out exactly for the bend you choose. For offsets and 3-point saddles, it uses the sine and tangent of the bend angle. Those are standard triangle ratios on any scientific calculator. That way you see where the familiar chart values (2 for 30°, 1.414 for 45°, 1/4 in of shrink per inch) come from. It also turns every answer into the nearest sixteenth of an inch for your tape. Stub-up and back-to-back marks use your bender's take-up. It is a layout aid. How a particular bender and conduit behave in practice still needs a test bend.

Where it's used

Why this math matters outside the classroom:

• Clearing a beam. An electrician jogs a run 6 in around a beam with two 30° bends 12 in apart, because 6 ÷ sin 30° = 12.
• Stub-ups at a panel. For an 11 in stub on a 1/2 in EMT bender with 5 in of take-up, the mark goes 6 in from the end.
• Saddling a pipe. To cross a 2 in pipe with a 45° saddle, the outer marks sit 2 × 2.613 ≈ 5 1/4 in either side of the center mark.
• Apprentice practice. Apprentices check bender charts by computing 1 ÷ sin θ and tan(θ ÷ 2) for 10°, 22.5°, 30°, 45° and 60°.
• Trig in context. Students see the hypotenuse of a right triangle as the conduit between two bends and the opposite side as the offset depth.

Grade level and standards: Grades 9–10; Common Core State Standards for Mathematics HSG.SRT.C.8. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.

How to use it

1. Choose the bend: an offset, a 90° stub-up, a back-to-back 90, or a 3-point saddle.
2. For an offset, enter the depth, the bend angle and the distance from the conduit end to the obstacle.
3. For a stub or back-to-back bend, enter the height or the distance between the backs of the bends. Then pick your bender or type its take-up.
4. For a saddle, enter the obstacle's height, the distance to its center and the center bend angle. Then read the marks.

What the inputs mean

Offset depth

The depth is how far the run moves sideways or up. Measure it between the centerlines (or outsides) of the conduit before and after the offset.

Distance from the conduit end to the obstacle

Measure from the end of the conduit you will bend toward to the point where the offset must be finished. The calculator adds the shrink, because the bends shorten the run.

Stub-up height

From the floor (or back of the bend) to the end of the conduit.

Bender

Take-up is how much length the bend uses when you bend a stub toward the end of the stick. Common hand benders for 1/2, 3/4 and 1 in EMT (thin-wall steel conduit) take up 5, 6 and 8 in. Still, check the marks on your own bender.

Take-up (deduct) of your bender

Marked on the bender or in its instructions.

Center bend

The center bend is twice each side bend. A 45° center with 22.5° sides is the most common. A 60° center with 30° sides suits taller obstacles.

Formula and method

Offset:  multiplier = 1 ÷ sin θ        distance between marks = depth × multiplier
         shrink = depth × tan(θ ÷ 2)    first mark = distance to obstacle + shrink
         second mark = first mark − distance between marks
Stub-up: mark = stub height − take-up
Back-to-back: mark = distance between backs (bend on the star)
Saddle:  side angle = center angle ÷ 2;  spacing = height ÷ sin(side angle)
         shrink = height × tan(side angle ÷ 2);  center mark = distance + shrink

In the formulas, θ (the Greek letter theta) is the bend angle. Sin and tan are the sine and tangent of an angle, standard triangle ratios. Depth is the offset depth, and take-up is your bender's deduct. Shrink is how much shorter the run gets because of the bends.

An offset forms a right triangle. The slanted conduit between the bends is the long side (the hypotenuse). The depth is the side across from the bend angle. So the slanted length is depth ÷ sin θ. The run uses that slanted length to cover a shorter straight distance. The difference is depth × (1 ÷ sin θ − 1 ÷ tan θ). That simplifies to depth × tan(θ ÷ 2), which is the shrink.

A 3-point saddle is two offsets back to back that share the center bend. Each side climbs the obstacle height at the side angle. So the outer marks sit height ÷ sin(side angle) from the center. The center mark moves forward by one side's shrink. Bender charts round these values: 2.5 instead of 2.613 for a 45° saddle, and 3/16 in of shrink per inch.

Worked example

A run of 1/2 in EMT must jog 6 in around a beam. The beam's face is 36 in from the end of the stick, and you're using 30° bends.

1. Multiplier: 1 ÷ sin 30° = 2.
2. Distance between marks: 6 × 2 = 12 in.
3. Shrink: 6 × tan 15° = 6 × 0.2679 = 1.6077 in. (Charts say 1/4 in per inch, which gives 1.5 in.)
4. First mark: 36 + 1.6077 = 37.6077 in, about 37 5/8 in from the end.
5. Second mark: 37.6077 − 12 = 25.6077 in, about 25 5/8 in.

Result: Make the two 30° bends 12 in apart, at about 37 5/8 in and 25 5/8 in from the end.

Understanding the result

Shallow angles such as 10° and 22.5° give long, gentle offsets. They shrink the run very little and make wire pulls easier. Angles of 45° and 60° fit tight spaces, but they shrink more and make the wire harder to pull.

The fraction under each result is the measurement rounded to the nearest 1/16 in. Bends are rarely more accurate than that. So make a test bend on scrap when the fit matters.

For a stub, the mark lines up with the bender's arrow. For a back-to-back bend made with the star method, the mark lines up with the star (the back-of-bend point). Then you bend toward the measured end.

Assumptions and limitations

• Bends are treated as sharp corners at the marks. Real bends are curved. The chart and trade methods allow for that in the take-up and the bender's markings.
• Offsets are measured to the obstacle along the conduit, from the end you bend toward.
• Take-up values are typical for common EMT hand benders. Your bender's own markings come first.
• It does not work out gain or the developed length of a bend. Those are what you'd need to cut conduit to length before bending.
• Rolling offsets (offsets in two directions at once), kicks and 4-point saddles are not covered.
• Raceway installation must follow the electrical code and the inspector's requirements. That includes the limit on total bend degrees between pull points. Electrical work should be done or checked by a licensed electrician.

Frequently asked questions

Sources

• Elliott Electric Supply: Conduit bending instructions (EMT bender), take-up values (checked 2026-10-19)
• Bill Bamford, Bending conduit/tubing using hand benders (Mike Holt Enterprises), multiplier and saddle charts (checked 2026-10-19)

How this calculator is checked

Method: Right-triangle trigonometry: offset spacing = depth ÷ sin θ, shrink = depth × tan(θ/2); saddle sides at half the center angle. Results agree with the multiplier and shrink charts in Bamford's hand-bending guide (Mike Holt Enterprises). Stub mark = height − take-up with 5/6/8 in take-ups for 1/2, 3/4 and 1 in EMT benders (Elliott Electric guide). The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.

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