Calculator Inputs
Example Data Table
| Case | Horizontal | Vertical | Advance | True Offset | Travel | Required Angle |
|---|---|---|---|---|---|---|
| Example A | 12.000 in | 9.000 in | 24.000 in | 15.000 in | 28.302 in | 32.005° |
| Example B | 18.000 in | 6.000 in | 30.000 in | 18.974 in | 35.496 in | 32.311° |
| Example C | 8.000 in | 14.000 in | 20.000 in | 16.125 in | 25.690 in | 38.884° |
These sample values help verify travel distance, true offset, and required fitting angle before field work begins.
Formula Used
True Offset = √(Horizontal Offset² + Vertical Offset²)
Travel = √(True Offset² + Advance²)
Required Angle = arctan(True Offset ÷ Advance)
Plan Angle = arctan(Vertical Offset ÷ Horizontal Offset)
Face to Face = Travel − 2 × Takeout
Cut Length = Face to Face − 2 × Cut Loss + Allowance
Compatible Advance = True Offset ÷ tan(Selected Angle)Compatible Travel = True Offset ÷ sin(Selected Angle)
How to Use This Calculator
- Enter horizontal offset, vertical offset, and advance using one consistent unit.
- Enter the elbow angle you expect to use in fabrication.
- Add fitting takeout, cut loss, allowance, pipe outside diameter, and quantity if needed.
- Select your preferred unit label and decimal precision.
- Press the calculate button to show results above the form.
- Review the graph, interpretation note, and compatibility values before cutting material.
- Download a CSV file for spreadsheets or a PDF for records.
Frequently Asked Questions
1. What is a rolling offset?
A rolling offset moves a line in two directions at once, usually sideways and vertically, while also advancing forward. It is common in piping, conduit, and structural layout work.
2. Which dimensions should use the same unit?
All linear inputs should use the same unit. That includes horizontal offset, vertical offset, advance, takeout, cut loss, allowance, and pipe outside diameter.
3. Why is the required angle different from the selected angle?
The required angle comes from your entered geometry. The selected angle is your intended fitting angle. If they differ, the entered advance and offset combination will not perfectly match that fitting angle.
4. What does true offset mean?
True offset is the combined sideways and vertical displacement. It is the diagonal offset in the offset plane before advance is considered.
5. Is travel the same as cut length?
No. Travel is the centerline distance along the rolled direction. Cut length is adjusted from travel using takeout, cut loss, and any added allowance.
6. What does plan angle tell me?
Plan angle shows how the vertical and horizontal offsets relate inside the offset plane. It helps you understand the roll direction before considering forward advance.
7. Why include pipe outside diameter?
Pipe outside diameter helps estimate remaining clearance after the true offset is established. It is useful when checking spacing, crowding, or clash risks during installation.
8. When should I add allowance?
Add allowance when you intentionally need extra material for field fit-up, trimming, welding preparation, or installation tolerance. Leave it at zero if no extra length is required.