True offset
10 in
Free field-layout geometry tool
Rolling Offset Calculator
Calculate true offset, travel, advance, bend angle, and rolling angle for conduit, pipe, tubing, and general two-plane layout work.
Field layout geometry
Rolling offset inputs
Travel, advance, and angle
Quick examples
Travel
20 in
Advance
17.32 in
Bend angle
30 deg
Rolling angle
36.87 deg
Horizontal offset
8 in
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What it is
A rolling offset calculator helps lay out a rolling offset when a run has to move in two planes at once. Instead of making only a single side offset or only a vertical rise, a rolling offset combines both into one true offset and then solves the bend geometry from that result.
In practical field work, people often care about the same core questions: what is the true offset, what bend angle is required, how much travel is needed between bends, and how much advance the layout consumes along the run.
This tool is meant for planning and layout. It helps turn a rolling offset into usable field numbers before bending or fabricating conduit, tubing, or pipe.
Why it matters
Rolling offsets are easy to misjudge because the layout happens in more than one direction at once. The side offset and rise may each look simple alone, but together they create a longer true offset and a different travel distance than many people expect.
A practical calculator helps avoid layout mistakes, wasted bends, and rework. That matters whether the job is conduit, pipe, tubing, or general fabrication where a two-plane offset has to land accurately.
Two-plane offsets are not intuitive
Horizontal and vertical offsets combine into a larger true offset than either one alone.
Travel changes with angle
Shallow bends increase travel quickly, while steeper bends shorten it.
Rolling angle helps with orientation
Knowing how the offset is split between horizontal and vertical directions helps with layout and field alignment.
Small layout misses compound fast
A wrong travel or angle can put the run off target once the roll and offset are combined.
How it works
The calculator starts by combining the horizontal offset and vertical offset into a single true offset. That is the straight-line offset created when both directions are present at the same time.
From there, it solves the rest of the geometry using one of three modes: known bend angle, known travel, or known advance. That makes it usable whether you are starting from a field angle or backing into the bend from available space.
Step 1: Combine the two offsets
Horizontal offset and vertical offset are combined into the true offset using right-triangle geometry.
Step 2: Solve bend geometry
Depending on the mode, the calculator solves for angle, travel, or advance from the known values.
Step 3: Calculate rolling angle
The rolling angle shows how the offset is oriented between the horizontal and vertical directions.
Step 4: Return field values
The outputs are travel, advance, true offset, bend angle, and offset orientation for layout use.
Core formulas
True Offset = sqrt(horizontal offset^2 + vertical offset^2)
When the bend angle is known: Travel = True Offset / sin(angle)and Advance = True Offset / tan(angle).
Quick reference examples
These examples show why rolling offsets feel different from a simple single-plane offset.
| Example | Why it matters |
|---|---|
| Conduit around a corner and up | A side move plus a rise creates a larger true offset than either change alone. |
| Pipe clearing structure in two directions | Available travel may drive the bend angle rather than the other way around. |
| Tubing layout with known bend angle | The true offset controls travel and advance even when the angle is fixed. |
| Limited straight run | Advance and travel help show whether the rolling offset fits in the space available. |
How to use the tool
- 1
Choose the solve mode
Pick whether you know the bend angle already, the travel between bends, or the straight advance available.
- 2
Enter the horizontal and vertical offsets
These are the two separate directional changes the run needs to make.
- 3
Enter the known layout value
Add the angle, travel, or advance depending on the selected solve mode.
- 4
Review the true offset and travel
These values are the most useful for field layout and checking whether the offset fits the run.
- 5
Use the rolling angle as an orientation guide
It helps show how the rolling offset is split between the two planes.
Real-world applications, edge cases, and limitations
Conduit and tubing layout
Useful for field bending and layout where a run has to move in two directions at once.
Space-check planning
Helpful for checking whether a rolling offset can fit within the available straight run.
Orientation guidance
Rolling angle and offset share help show how the offset is distributed in the two planes.
Estimate limitations
Real field bends can still vary because of material spring-back, bend radius, shoe type, and trade-specific layout methods.
This tool is best used as a layout and planning calculator. It gives a clean geometry baseline before bending or fabrication starts, which is exactly where many rolling-offset mistakes are easiest to prevent.
It is not a substitute for trade-specific field rules, bender charts, or fabrication tolerances. Material type, bend radius, shoe selection, and field method can still affect the exact physical result.
Frequently asked questions
- What is a rolling offset?
- A rolling offset is an offset that moves in two planes at the same time, usually combining a side offset with a rise or drop.
- What is true offset?
- True offset is the combined straight-line offset created by the horizontal and vertical offset components together.
- What is travel in a rolling offset?
- Travel is the center-to-center distance along the run between bends required to create the rolling offset.
- What is advance?
- Advance is the straight run consumed while creating the offset. It is useful for checking whether the layout fits in the space available.
Solve rolling offset geometry before you bend
Use this rolling offset calculator to calculate true offset, travel, advance, bend angle, and rolling angle before layout, bending, or fabrication starts.