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Pipe offset calculator: travel, run, and cut length

Type the offset and pick the angle (45, 22.5, 30, 60, 11.25, or any angle), the pipe size, and the elbow. The cut length comes out to the nearest 1/16 inch with both take-outs and both gaps already off, with the travel, the run, and every line of the arithmetic.

Whole inches, decimals, or fractions: 18 3/8, 18-3/8, or 18.375.

Fitting angle

Root gap at each butt weld. Not used with no fittings.

Runs in your browser. Nothing you type is stored or sent. Take-outs are the commonly published butt-weld values from the take-out chart: default values, check your fittings.

How this pipe offset calculator works

Travel = offset ÷ sin(angle) Run = offset ÷ tan(angle) Cut = travel − 2 × take-out − 2 × gap
  • At 45 degrees the fitting is a factory 45 LR butt-weld elbow, with the published center-to-end for the size.
  • At any other angle the fitting is a 90 LR or 90 SR cut down to the angle, with a take-out of the 90's center-to-end × tan(angle ÷ 2). See cutting down a 90.
  • None, center to center gives the travel with nothing taken off, for plumbing make-up you figure yourself.
  • Type my own take-out for threaded or socket-weld fittings, or a maker's value that differs from the chart.
  • The gap is taken off at both joints for butt-weld fittings. It is not used with no fittings.
  • Everything is computed in full and rounded once, at the end, so the cut can differ by a sixteenth from a hand calculation that rounds each step.

If the fittings cannot fit, it says so and gives the shortest offset that leaves 1/16 inch of pipe between them.

Check it against a known answer

A 10 inch offset at 45 degrees on 2 inch pipe with 45 LR elbows and a 1/8 inch gap should read: travel 14 1/8, run 10, take-outs 2 × 1 3/8, gap 2 × 1/8, cut 11 1/8. The multipliers line should read travel 1.414, run 1.000. At 22.5 degrees the multipliers are 2.613 and 2.414; at 30, 2.000 and 1.732; at 60, 1.155 and 0.577; at 11.25, 5.126 and 5.027.

Want the reasoning behind each line? Read the pipe offset formula, the 1.414 rule for 45 degree offsets, the 60 degree offset formula, or the multiplier chart. For rise and roll, use the rolling offset calculator.