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Welding Travel Speed Formula and Measurement

Calculate average travel speed from weld length and arc time, then use it correctly in arc-energy and heat-input calculations.

Published September 16, 2026Updated September 16, 2026Editorial method

Welding travel speed is the distance the arc progresses along the joint divided by arc time. Because it sits in the denominator of the arc-energy formula, an incorrect time basis or unit can materially distort the calculated energy per unit length.

Quick answer

Travel speed = weld length ÷ arc time

If length is in millimeters and time is in minutes, the result is mm/min. Multiply mm/s by 60 to obtain mm/min.

In this guideFormulaWorked exampleHow to measureHeat-input link

Travel-speed formula and conversions

Average travel speedv = L / tL = arc travel distance · t = arc-on time
  • mm/min = weld length in mm ÷ arc time in minutes
  • in/min = weld length in inches ÷ arc time in minutes
  • mm/min = mm/s × 60
  • in/min = mm/min ÷ 25.4

Worked example

A continuous weld bead is 250 mm long and the measured arc-on time is 50 seconds.

  1. Convert time: 50 ÷ 60 = 0.8333 min.
  2. Travel speed: 250 ÷ 0.8333 = 300 mm/min.
  3. Imperial equivalent: 300 ÷ 25.4 = 11.811 in/min.

If the same pass uses 24 V and 200 A, its arc energy is 24 × 200 × 60 ÷ (300 × 1,000) = 0.960 kJ/mm before any efficiency factor.

Measure the time basis consistently

Use arc-on time for the continuous length represented by the electrical readings. Do not include setup, repositioning, crater fill, or an interpass pause unless the governing method explicitly requires it. For stitch welds, stops and starts make a single length/time average less representative; document the measurement method.

Mechanized welding may provide commanded travel speed, but actual motion should still be confirmed when accuracy matters. Manual welding varies through the pass, so use a documented average or suitable data acquisition according to the applicable procedure.

Why travel speed changes energy per length

At constant voltage and current, doubling travel speed halves calculated arc energy per unit length. That does not mean the entire weld response is predicted by one value: joint geometry, preheat, interpass temperature, bead placement, process, waveform, and heat sinking also affect thermal history.

  • Measure length along the actual weld path.
  • Convert seconds to minutes before using a per-minute formula.
  • Use units that match the desired kJ/mm or kJ/in output.
  • Record average electrical values using the required method.
  • Compare the result with the qualified WPS/PQR and applicable code.

Technical references

Published and formula-checked by MfgWorkbench. Last reviewed September 15, 2026. See our editorial method.

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