Rolling Offset Calculator

Metric Imperial
Travel (T): 0.00 m
Run (R): 0.00 m
True Offset (c): 0.00 m

Rolling Offset Diagram

H (Horizontal Offset) V (Vertical Offset) R (Run) θ θ T (Travel)

The diagram shows the pipe path with two elbows creating the rolling offset.

How it works

A rolling offset in piping is used when a pipe needs to change direction both horizontally and vertically simultaneously. This calculator helps you determine the travel length (the actual pipe length needed) and the run (the straight-line distance between the two endpoints in the plane of the offset).

The calculation uses the horizontal offset (H), vertical offset (V), and the bend angle (θ) of the fittings to compute the required pipe measurements.

Formula

The calculations are based on the following formulas:

  • True Offset (c) = √(H² + V²)
  • Travel (T) = c / sin(θ)
  • Run (R) = √(T² – c²)

Where θ is the bend angle in radians (converted from degrees).

Multiplier Table

For common bend angles, here are the multiplier values used to calculate travel:

Bend Angle Multiplier (1/sinθ)
22.5° 2.6131
30° 2.0000
45° 1.4142
60° 1.1547
90° 1.0000

Example Calculation

For a rolling offset with:

  • Horizontal Offset: 100 cm
  • Vertical Offset: 50 cm
  • Bend Angle: 45°

The calculations would be:

  • True Offset (c) = √(100² + 50²) = √(10000 + 2500) = √12500 ≈ 111.80 cm
  • Travel (T) = 111.80 / sin(45°) = 111.80 / 0.7071 ≈ 158.11 cm
  • Run (R) = √(158.11² – 111.80²) = √(25000 – 12500) = √12500 ≈ 111.80 cm

FAQs

What is a rolling offset?
A rolling offset is a piping configuration where a pipe changes direction both horizontally and vertically using two angled fittings (usually elbows). This creates a three-dimensional offset rather than a simple horizontal or vertical bend.
Why are two elbows used in a rolling offset?
Two elbows are used to create both the horizontal and vertical components of the offset while maintaining a smooth flow path for the fluid in the pipe. Using two angled fittings allows the pipe to “roll” around obstacles in both horizontal and vertical planes.
Can I use custom bend angles?
Yes, this calculator supports custom bend angles. Simply select “Other (custom)” from the bend angle dropdown and enter your desired angle in degrees (between 1° and 179°).
What units can I input?
You can use metric units (mm, cm, m) or imperial units (in, ft). Use the toggle switch to switch between measurement systems.
Is the true offset the same as travel?
No, the true offset (c) is the straight-line distance between the start and end points of the offset. The travel (T) is the actual length of pipe needed, which is longer due to the angled fittings.