Heat Input Calculator
Full ISO/TR 18491 treatment with process efficiency factors and per-step working.
No need to switch between a Heat Input calculator, stopwatch app or wristwatch. Press Start when welding begins and Stop when it ends. Enter the welding parameters before, during or after welding.
HeatInput records Arc Time and automatically calculates Travel Speed, Arc Energy and Heat Input in one continuous workflow.
Fewer taps. No manual time conversion. No switching between apps.
Save, compare and document welding measurements in one clear workflow.
Review key parameters, averages and results, then export, email or report your saved runs.


Heat input strongly influences the t8/5 cooling time, which affects HAZ microstructure, hardness and susceptibility to hydrogen cracking.
Excessive heat input can promote grain growth and reduce strength and impact toughness, depending on the material and welding conditions.
Qualified welding procedures may include heat input limits or related essential variables. Production welding must remain within the applicable WPS and qualification range.
Full ISO/TR 18491 treatment with process efficiency factors and per-step working.
Gross energy per unit length as reported under AWS D1.1 and ASME IX.
Derive true travel speed from measured weld length and arc-on time.
Switch systems instantly. Every result carries its equivalent conversion.
Live recalculation as you type — no submit buttons, no page reloads.
Formula, variables, calculation steps and rounding shown for every output.
Help us understand which features matter most to you.
No account required. Three welding calculators with detailed results in Metric and Imperial units.