Welding Amperage Calculator
Pick your process, material, and thickness to get a recommended amperage range and wire speed. Adjust for joint type and welding position. Shielding gas and preheat guidance included. Nothing uploaded.
Recommended Amperage
Wire Feed Speed ?
Guidance
These are starting-point guidelines. Always verify with your welder's manual and test on scrap first.
Learn more: amperage settings, metal thickness, and wire diameter
Why correct amperage matters: porosity, weakness, and burn-through
Amperage (measured in amps) controls the heat input to the weld. Too little amperage produces a weak, porous weld that fails under stress. Too much amperage causes burn-through (the metal melts completely through the gap), spatter, and uncontrolled penetration. The correct range produces a bead that melts the base metal cleanly, fuses with the filler metal, and cools with proper metallurgical structure.
How metal thickness, wire diameter, and travel speed interact
Thick material needs higher amperage to heat it through. Thinner material needs lower amperage to avoid melt-through. Larger diameter wire (0.045 inch vs 0.030 inch) also requires higher amperage because it carries more filler. Travel speed (how fast you move along the joint) affects heat input per unit length - slower travel time means more time for heat to soak in, so faster travel needs higher amperage.
MIG vs TIG and their different amperage requirements
MIG (Metal Inert Gas, also called GMAW) uses a constant wire feed rate and the machine adjusts voltage automatically - you mainly set amperage. TIG (Tungsten Inert Gas, also called GTAW) uses a non-consumable tungsten electrode and you manually feed filler rod and control amperage independently. Both processes have recommended amperage ranges based on material thickness and wire diameter.
FAQ
What amperage should I use for MIG welding 1/4 inch steel?
For 0.030 inch wire, roughly 140-180 amps depending on travel speed and shielding gas. Thicker wire (0.035 or 0.045 inch) uses higher amperage (180-250 amps). Start at the lower end and increase amperage until you get a smooth, consistent bead without spatter or porosity.
What is the difference between amperage settings on MIG and TIG?
MIG is typically constant amperage with automatic voltage control. TIG is true constant amperage where you control both amperage and voltage manually. TIG gives more precise control and works better for thin materials and aluminum.
Can I use the same amperage for different wire diameters?
No. Larger diameter wire requires higher amperage (roughly 1 amp per 0.001 inch of diameter). Using too low amperage with thick wire produces incomplete fusion; too much amperage with thin wire causes burn-through and excessive spatter.