Practical tools for measured work
Pipe Offset Travel & Run Multiplier Calculator
Calculate travel and run for a same-plane pipe offset from the offset distance and fitting angle, with the standard multiplier chart.
Perpendicular distance between the two pipe centerlines
Angle of each elbow from the original run, e.g. 22.5, 30, 45, 60
Travel = Offset x (1 / sin angle). Run = Offset x (1 / tan angle). Both fittings use the same angle for a same-plane offset.
How it works
Offset, travel and run: offset is the perpendicular distance between the original pipe centerline and the new, parallel centerline it needs to reach. Travel is the length of pipe between the two fitting centers (the diagonal run). Run - sometimes called advance or setback - is the distance covered in the original direction of flow.
Formula. Travel = Offset ÷ sin(angle). Run = Offset ÷ tan(angle). Both constants come from a single fitting angle used at both ends of the offset - this is the standard same-plane, equal-angle offset, not a rolled (two-plane) offset.
Standard multiplier chart. Fabricators commonly memorize or look up these constants instead of recalculating sin/tan each time:
| Fitting angle | Travel constant | Run constant |
|---|---|---|
| 5° | 11.474 | 11.430 |
| 10° | 5.759 | 5.671 |
| 11.25° | 5.126 | 5.027 |
| 15° | 3.864 | 3.732 |
| 20° | 2.924 | 2.747 |
| 22.5° | 2.613 | 2.414 |
| 30° | 2.000 | 1.732 |
| 45° | 1.414 | 1.000 |
| 60° | 1.155 | 0.577 |
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Offset
- 100 mm
- Fitting angle
- 45 deg
Primary result: Travel: 141.4 mm.
Before using the result
- Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
- Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
- When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.
Limitations
This is the same-plane offset case only. A rolled offset (rise and lateral displacement together, needing two mitered elbows turned to a diagonal) is a different calculation - use the Duct Rolled-Offset tool for that. This tool does not account for fitting takeoff (the fitting's own center-to-end dimension) - subtract that separately when marking cut length.
Frequently asked questions
Which angle should I use?
Whatever angle your fittings actually are. 45° and 22.5° are the most common stock elbow angles, but the formula works for any angle up to (not including) 90°.
What is the run used for?
Run tells you how far along the original pipe run the offset fittings will land, so you can mark the cut point on the straight pipe before installing the first elbow.
Does this include the fitting's own takeoff dimension?
No. Travel and run describe the geometry between fitting centerlines. Use a fitting takeoff calculator to convert that into an actual cut length for your specific fittings.
Related tools
Pipe Offset Clocking
Convert vertical and lateral offsets into near/far-end clock positions and circumference marks from an established datum.
Pipe Fitting Takeoff
Deduct user-supplied fitting center-to-end dimensions from field measurements to find a pipe cut length.
Duct Rolled Offset
Calculate rolled-offset travel, advance and roll angle, with a printable mitered-elbow cut template.
Bend Allowance Calculator
Calculate bend allowance, bend deduction and setback for a sheet metal bend, with a diagram.