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Conduit Bending calculator

Offset Bend Calculator

This offset bend calculator is a field-chart geometry screen for equal-angle conduit offsets. It returns distance between bends, shrinkage allowance, developed length, centerline advance, and optional bend-mark locations from one first-mark reference. It does not model bender-specific take-up, conduit material deductions, or NEC bend-radius compliance.

Updated June 21, 2026

A 4 in offset at 30 degrees uses 8.00 in between bends and about 1.00 in of shrinkage because 4 x 2.0 = 8 and 4 x 0.25 = 1.

Spacing = offset depth x multiplier | 3 in at 45 degrees -> 3 x 1.414 = 4.242 in between bends.

Enter offset depth, bend angle, and an optional first-mark reference to screen bend spacing, shrinkage, travel, and mark layout.

Calculator Inputs

Quick Presets

Vertical rise needed to clear the obstruction or change elevation.

Choose the equal angle used for both bends in the offset.

Leave blank if you only want relative spacing. Enter a first-mark reference if you want both bend marks returned.

Calculation Results

Enter values above to see calculation results

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Calculation history

Example Calculations

4 inch offset at 30°

Common field layout with an 8 inch spacing and about 1 inch of shrinkage.

Inputs
  • Offset Depth: 4
  • Bend Angle: 30 degrees
  • First Mark Distance: 12

3 inch offset at 45°

Shorter spacing screen for a tighter offset.

Inputs
  • Offset Depth: 3
  • Bend Angle: 45 degrees

How to Use

How to use the offset bend calculator

An offset bend uses two equal bends to move a conduit run up, down, left, or right while keeping the run parallel. This page uses common field multipliers and shrinkage allowances for standard bend angles.

1. Enter the offset depth

  • The offset depth is the vertical rise needed to clear an obstruction or change elevation.
  • Use inches to match the field chart values on this page.

2. Choose the bend angle

  • Shallower bends need more spacing between marks.
  • Steeper bends reduce spacing, but they increase shrinkage and are usually harder to execute cleanly.

3. Add a first-mark reference only when you need absolute locations

  • Leave the first-mark distance blank when you only want relative spacing.
  • If you already know the first bend mark, enter it and the page will return both bend marks.

4. Read the result as a layout screen

  • Distance between bends uses the field multiplier for the selected angle.
  • Shrinkage allowance uses a common field allowance, not a code rule.
  • Developed length and centerline advance are geometry references for the finished offset section.

Common field multipliers and shrinkage allowances

Bend angle Multiplier Shrinkage per inch Typical field use
10° 6.0 1/16" Very gradual offset
15° 3.9 1/8" Gentle field offset
22.5° 2.6 3/16" Moderate offset
30° 2.0 1/4" Common field angle
45° 1.414 3/8" Tighter spacing
60° 1.155 1/2" Very compact offset

Example: a 4 inch offset at 30° uses the common 2.0 multiplier, so spacing between bends is 4 × 2.0 = 8 inches. With a 1/4 inch shrink allowance per inch of offset, shrinkage is about 4 × 1/4 = 1 inch.

For obstacle saddles, use the saddle bend calculator. For single kicks, use the kick bend calculator. For equal-angle segmented curves, use the segment bend calculator.

Common Applications

Laying out a standard two-bend conduit offset with common field multipliers

Checking bend spacing before marking EMT or rigid conduit in the field

Reviewing shrinkage allowance for one selected offset angle

Getting first and second bend marks from a known first-mark reference

Comparing shallow and steep offset geometry before bending

Frequently Asked Questions

What is the most common angle for an offset bend?
30° is a common field choice because the spacing math is easy: distance between bends is about 2 times the offset depth. It is a practical balance between longer shallow offsets and tighter steeper offsets.
How do I calculate the distance between bends on an offset?
Multiply offset depth by the field multiplier for the selected angle. For a 4 inch offset at 30°, spacing is 4 × 2.0 = 8 inches. For a 3 inch offset at 45°, spacing is about 3 × 1.414 = 4.242 inches.
Why does this page not ask for conduit type or conduit size?
This page is scoped to geometry and common field-chart allowances only. It does not attempt to model bender-specific take-up, conduit stiffness, or size- and material-specific behavior, which can vary in real field work.
What is shrinkage in an offset bend?
Shrinkage is the common field allowance used to account for how the finished offset changes layout length through the bend section. The calculator shows a quick allowance for the selected angle, but you should still verify the result with the actual bender and conduit in use.
Is this calculator a code-compliance check?
No. It is a geometry screen for offset layout. It does not determine NEC minimum bend radius, conduit-fill limits, or bender-specific compliance.

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