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Pipefitting math guides: offsets, take-outs, and cut length
The arithmetic behind a pipe offset, written out once, with worked examples you can check on a calculator. Each guide opens with the short answer, then the reasoning, the steps, and the mistakes that cost a piece of pipe.
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Pipe offset formula: travel, run, and cut length
Every term defined (offset, travel, run, take-out, gap, true offset), the two trig formulas, the cut length formula, and how they fit together. The other guides build on this one.
Read the pipe offset formulaOffsets
The 1.414 rule: 45 degree offsets
Offset × 1.414 for the travel, the run equal to the offset, why 1.414 is the square root of 2, a travel chart, and worked cut lengths.
60 degree offset formula
Offset × 1.155 for the travel and × 0.577 for the run, where the numbers come from, a chart, and cut lengths with 90s cut to 60.
Rolling offset formula
True offset from rise and roll, travel and run from the angle, the setback method, and how far to roll the fittings.
Offset multiplier chart
1.414, 2.613, 5.126 and the rest: travel and run multipliers from 5 to 85 degrees, and why small angles punish small errors.
Fittings and cut length
How to figure take-outs and cut length
Travel minus a take-out per fitting minus a gap per weld, for butt-weld, threaded, and socket-weld pipe, and why offsets come up long.
Pipe take-out chart
Center-to-end for 90 LR, 90 SR, and 45 LR butt-weld elbows, 1/2 to 12 inch, in fractions and decimals.
Take-out of a 90 cut to any angle
R × tan(angle ÷ 2), a factor table, and where to mark the cut on the heel and the throat.
Check a number in the browser
Pipe offset calculator
Any angle, pipe size, and elbow. Cut length with take-outs and gaps off, to 1/16.
Rolling offset calculator
Rise and roll with an angle or a setback. True offset, travel, run, and cut.
These guides explain arithmetic. They are not a substitute for your drawings, your fittings, or your welding procedure. Verify measurements before cutting.