welding calculator
Weld Heat Input Calculator
Calculate arc heat input per inch and per millimeter from voltage, current, travel speed, and thermal efficiency.
How it works
Heat input = (voltage x current x 60 x efficiency) / (travel speed in/min x 1000).
Worked example
25 V, 150 A, 12 in/min, 0.8 efficiency: 15 kJ/in (0.59 kJ/mm).
When to use it
- Thermal efficiency: SMAW/GMAW ~0.8, GTAW ~0.6, SAW ~1.0.
- WPS and PQR limits use heat input to avoid brittle or over-soft welds.
Related calculators
All results are an engineering estimate — not for custody transfer. Field measurement and certified tables govern.