How to use this calculator
- Enter the offset height. Measure the perpendicular distance the raceway must move to clear the obstruction or line up with the box.
- Choose the bend angle. Pick 10, 22.5, 30, 45 or 60 degrees, or enter a custom angle if your bender and layout call for it.
- Check straight-run space. Enter the available straight distance so the calculator can compare the projected offset run with the layout space.
- Check bend budget. Add any existing bends in the same pull section and review the remaining 360-degree screen before committing the route.
How it works
A two-bend offset is a right-triangle geometry problem. The offset height
is the opposite side of the bend angle, and the straight conduit between
bend points is the hypotenuse:
D = h / sin(a)
where D is distance between bend marks, h is the
offset height and a is the angle of each bend.
The shrink allowance comes from the same geometry: S = h x tan(a / 2) The projected run between bend points is R = D x cos(a) which is the straight-route distance consumed by the offset. The page also totals the two bend angles and subtracts them, plus any entered existing bends, from a 360-degree pull-section screen.
Conduit Offset Multiplier Chart
These common offset multipliers come directly from 1 / sin(angle).
Shrink per inch of offset is tan(angle / 2), so multiply the
shrink value below by the actual offset height.
| Bend angle | Offset multiplier | Shrink per inch of offset | Field read |
|---|---|---|---|
| 10 degrees | 5.76 | 0.09 in | Gentle offset; long mark spacing. |
| 22.5 degrees | 2.61 | 0.20 in | Common field compromise. |
| 30 degrees | 2.00 | 0.27 in | Easy mental math; common EMT layout. |
| 45 degrees | 1.41 | 0.41 in | Shorter spacing; more bend total. |
| 60 degrees | 1.15 | 0.58 in | Compact offset; high bend total. |
Treat the chart as ideal centerline geometry. Actual field marks still depend on the bender reference, conduit size, shoe radius and manufacturer instructions.
Conduit Bend Offset Worksheet
Use this worksheet flow when the search is for a conduit bend offset worksheet instead of only a multiplier chart. It keeps the field layout steps in order and points each value back to the calculator output.
| Worksheet line | What to enter or record | Calculator output |
|---|---|---|
| Offset height | Measure the perpendicular rise or drop around the obstruction. | h |
| Bend angle | Choose 10, 22.5, 30, 45, 60 or a custom angle your bender supports. | a |
| Mark spacing | Multiply offset height by the angle multiplier. | D = h / sin(a) |
| Shrink allowance | Move the far-end reference by the calculated shrink for the two-bend offset. | S = h x tan(a / 2) |
| Straight-run check | Compare projected run with available straight space before nearby boxes or couplings. | R_margin |
| Pull-section bend budget | Add existing bends and confirm the offset does not exhaust the bend budget. | B_rem = 360 - B0 - 2a |
Pair this page with the conduit fill calculator once conductor count and raceway size are known, the conduit bend offset formula page for formula-first searches, the electrical box fill calculator for outlet, switch or junction box volume, the voltage drop calculator for wire size and length, the conduit pull tension calculator for pulling tension and sidewall pressure, and the transformer kVA calculator when source capacity is part of the same layout.
Worked example
Verified against the live calculator
For a 4 in offset using 30 degree bends,
the multiplier is 1 / sin(30) = 2.00, so the distance between
marks is 8.0 in. Shrink is
4 x tan(15) = 1.07 in. The projected run between bend points is
about 6.93 in, and the two bends add 60 degrees
to the pull-section bend total.
Frequently asked questions
How do you calculate a conduit offset bend?
For two equal offset bends, divide the desired offset height by sin(angle) to get the distance between bend marks. The shrink allowance is offset height multiplied by tan(angle / 2).
What conduit offset multiplier should I use?
The exact multiplier is 1 / sin(angle). Common values are about 5.76 for 10 degrees, 2.61 for 22.5 degrees, 2.00 for 30 degrees, 1.41 for 45 degrees and 1.15 for 60 degrees.
What should a conduit bend offset worksheet include?
A useful worksheet records the offset height, bend angle, multiplier, distance between bend marks, shrink allowance, projected run, existing pull-section bends and remaining bend budget. That keeps layout geometry, space and pull-point limits visible before field marking.
What is shrink in conduit bending?
Shrink is how far the far end of the conduit moves back because the offset bends replace part of the straight run. For a two-bend offset, the geometry screen is shrink = offset x tan(angle / 2).
Does this replace bender instructions?
No. The calculator gives the geometry. Field marks still depend on the bender type, shoe radius, conduit size, the arrow/star/teardrop reference used, local code and whether the run needs a pull point.
Method & assumptions
- Two equal bends create the offset; rolling offsets, three-bend saddles and kicked 90s are not modeled.
- Distance between bend marks uses ideal centerline geometry, not a specific hand-bender take-up chart.
- Shrink is the geometric end shift for the two-bend offset; field mark direction still depends on the reference end and bend sequence.
- The 360-degree result is a routing screen only. Verify adopted code, local amendments, pull points, bend radius, pulling tension, supports, box locations and manufacturer bender instructions.