How a simple offset is worked out
An offset moves a run of pipe over to a new line using two fittings of the same angle. The distance it moves over is the set. The diagonal piece between the two fittings, measured centre to centre, is the travel.
travel = set × travel constant (1 ÷ sin angle)
run = set ÷ tan(fitting angle)
Example: a 12" set with 45° fittings. 12 × 1.414 = 16.97", so the travel is 1' 5" to the nearest sixteenth and the run is 12".
Travel constants by fitting angle
| Fitting angle | Travel = set × | Run = set × |
|---|---|---|
| 11¼° | 5.126 | 5.027 |
| 22½° | 2.613 | 2.414 |
| 30° | 2.000 | 1.732 |
| 45° | 1.414 | 1.000 |
| 60° | 1.155 | 0.577 |
| 72° | 1.051 | 0.325 |
Travel is not the cut length
Travel is centre to centre of the fittings. To cut the pipe, take off each fitting's take-out and the gap at each joint. The free cut length calculator does that step if you know your take-outs.
This page does one job and needs internet. CutRight does the whole job with no signal.
This free calculator only gives you the travel on a simple offset, and it only works while you have a connection. The CutRight app works fully offline and goes further: rolling and odd-angle offsets, the actual cut length with each fitting's take-out from the published tables, saddle templates, mitered bends and pipe data. Pay once, no subscription.