How long do you cut a pipe offset?
Enter how far the pipe has to shift and pick the fitting angle — get the travel (the diagonal pipe to cut), the run and the offset instantly, in inches or millimetres, with rolling offsets handled too.
Travel is the length between the two fittings, measured centre-to-centre. Subtract each fitting's take-off (the make-up from the centreline to the pipe stop) to get the pipe cut length.
travel = offset × 1.414 · run = offset × 1.000 for 45° fittings. Multipliers are exact trigonometry — the same in every country.
Want the full method, the fitting-angle multiplier table and worked examples? Read: how to calculate a pipe offset →
Common questions
- How do you calculate a pipe offset?
- Measure the offset — how far the pipe has to shift sideways — then divide by the sine of the fitting angle to get the travel (the diagonal pipe between the two fittings), and by the tangent of the angle to get the run (how far it advances along the line). For the common 45° offset that means travel = offset × 1.414 and run = offset. Enter the offset and pick the angle above and the calculator does both for you.
- What is the multiplier for a 45 degree offset?
- For 45° fittings the travel multiplier is 1.414 (that is 1 ÷ sin 45°, the square root of 2) and the run multiplier is 1.000 (1 ÷ tan 45°). So a 10-inch offset needs 10 × 1.414 = 14.14 inches of travel, and the run is also 10 inches. The 1.414 constant is the number pipefitters memorise for the 45° offset.
- What are travel and run on a pipe offset?
- Offset is the sideways distance the pipe moves; travel is the length of the diagonal pipe between the two fittings, measured centre-to-centre; and run is how far the offset advances in the original direction of the pipe. Offset and run are the two legs of a right triangle and travel is the hypotenuse, so travel is always the longest of the three.
- How do you calculate a rolling offset?
- A rolling offset shifts the pipe both across and up at the same time. First find the true offset with Pythagoras: offset = √(roll² + rise²). For example an 8-inch roll and a 6-inch rise give √(64 + 36) = 10 inches. Then treat that as an ordinary offset — travel = offset × 1.414 for 45° fittings. Switch the calculator to rolling mode and it works the true offset out for you.
- How do I turn travel into the pipe cut length?
- Travel is the centre-to-centre distance between the two fittings. To get the length of pipe to actually cut, subtract each fitting's take-off — the make-up distance from the fitting's centreline to the point where the pipe seats (the pipe stop or thread engagement). The two take-offs depend on the specific fittings and pipe, so read them from the fitting or lay one out, then take them off the travel figure.
Reference & education only. Not professional, engineering, or code-compliance advice. Estimates are based on published model codes; local amendments and your Authority Having Jurisdiction (AHJ) govern. Always verify against the current adopted code and a licensed professional before doing work.
Last reviewed 2026-07.