Calculator Form
Example Data Table
| Example | Bend Type | Height | Angle | Radius | Main Output |
|---|---|---|---|---|---|
| Offset around tray | Simple offset | 6 in | 30 degrees | 5 in | 12 in mark spacing, 1.6077 in shrink |
| Small pipe crossing | Three point saddle | 4 in | 22.5 degrees | 5 in | Center mark with equal outer spacing |
| Panel stub | Ninety degree stub up | 24 in | 90 degrees | 5 in | Stub mark equals height minus take up |
| Large sweep | Segment bend | Radius based | 90 degrees | 18 in | Equal bend angle and mark spacing |
Formula Used
Offset spacing: distance between bends = offset height ÷ sin(angle).
Offset shrink: shrink = offset height × tan(angle ÷ 2).
Three point saddle: outside spacing = saddle height ÷ sin(outer angle). Center bend = 2 × outer angle.
Four point saddle: total shrink = 2 × saddle height × tan(angle ÷ 2).
Stub up mark: mark = desired stub height − bender take up.
Arc length: bend allowance = centerline radius × bend angle in radians.
Segment bend: bend per shot = total angle ÷ number of segments. Mark spacing = arc length ÷ segments.
Gain estimate: gain = 2 × radius × tan(angle ÷ 2) − arc length.
How to Use This Calculator
- Select the bend type that matches your conduit layout.
- Choose the working unit used on your tape or rule.
- Enter the height, angle, radius, and mark values.
- Add clearance when the conduit must avoid a finished surface.
- Use the calculated marks as a field layout guide.
- Download CSV for records or PDF for a printable note.
- Make a test bend when exact fit is important.
Conduit Bending Guide
Practical Layout Basics
Conduit bending looks simple, but small layout errors grow quickly. A bend can move an outlet box, shorten a raceway, or create an ugly crossing. This calculator turns field notes into repeatable marks. It helps you compare common bend types before cutting pipe.
Offset Bend Planning
Use the offset option when a run must clear a beam, tray, panel edge, or finished surface. Enter the rise, bend angle, and first mark. The tool gives distance between marks and shrink. The shrink value shows how much the finished run pulls back. Add that amount when the final endpoint must stay fixed.
Saddle Bend Planning
The saddle options help when conduit must pass over an obstruction and return to the same line. A three point saddle uses one center bend and two outside bends. It works well for narrow obstructions. A four point saddle uses two equal offsets. It works better for wider objects because the top section stays straighter.
Stub Up Planning
The stub up option checks the mark for a ninety degree rise. Take up changes by bender size, shoe style, and conduit type. Enter the value printed on your bender when available. The gain estimate uses centerline radius and bend angle. It is a planning value, not a code substitute.
Segment Bend Planning
Segment bending is useful for large sweeps. Instead of one sharp bend, the angle is split into many small bends. More segments create a smoother curve. The calculator reports bend per shot, arc length, chord length, and mark spacing. These results support layout for sweeps around equipment or architectural features.
Field Accuracy Tips
Always measure from a clear reference point. Mark the conduit on a flat surface. Keep the bender arrow, star, or rim aligned with the mark required by your method. Check that all bends face the correct direction before making the next shot. Rotate carefully when saddles need to stay in one plane.
Final Checks
Treat every answer as a layout aid. Real conduit springs back. Bender markings vary. Job rules may require different radii or minimum cover. Make a test bend when precision matters. Record your actual take up, gain, and shrink notes. Those values improve the next run. Use labels on every conduit mark. Keep a pocket copy with project notes. Check faster during pulls on site each day.
FAQs
What does conduit shrink mean?
Conduit shrink is the pullback caused by bends. After an offset or saddle is bent, the finished end may be shorter than expected. Add shrink when the endpoint must land at an exact location.
Which angle should I use for an offset?
Common field angles are 10, 22.5, 30, 45, and 60 degrees. Smaller angles need more space but create smoother runs. Larger angles save space but are harder to pull.
What is bender take up?
Take up is the amount deducted from the desired stub height. It depends on conduit size and bender design. Use the value printed on your bender shoe when possible.
Can this calculator replace field testing?
No. It gives layout estimates. Real conduit may spring back. Bender marks may differ. Make a test bend when the final fit must be exact.
What is a three point saddle?
A three point saddle has one center bend and two outside bends. It lifts conduit over a narrow obstruction and returns the run to the original line.
What is a four point saddle?
A four point saddle uses two offset pairs. It works well for wider obstacles because the middle section can stay straight over the obstruction.
Why enter centerline radius?
Radius is needed for arc length, gain, and segment bend estimates. If you do not know it, use a measured bend radius or the bender specification.
Does the calculator support metric units?
Yes. You can choose inches, feet, millimeters, centimeters, or meters. Keep all distance inputs in the same unit for accurate results.