Welding thickness & amperage calculator
Enter the metal thickness. Get the TIG amps, the MIG wire and settings, or the stick rod and amperage range — the published rules of thumb, computed. Plus duty-cycle runtime math.
1/16" = 62 · 1/8" = 125 · 3/16" = 188 · 1/4" = 250
Sheet 16 ga ≈ 62 · 1/8" = 125 · 3/16" = 188
How long can you actually weld before the machine cuts out? Duty cycle is thermal — it scales with the square of the amperage ratio.
How these rules work
Welding sizing is built on three published approximations that machine makers have taught for decades. TIG: about 1 amp per 0.001 inch of mild steel — 1/8" steel starts near 125 A, aluminum wants ~1.5× that because it dumps heat fast. Stick: rod diameter ≈ half the base-metal thickness, then look up the amperage window for that rod size and type. MIG: wire size follows thickness (0.023" under 3/32", 0.030" through 3/16", 0.035" above), and wire speed scales with amps. None of these replace a test bead — every real shop tunes on scrap first.
Quick reference: thickness → power class
| Steel thickness | TIG amps | Stick rod | Machine class |
|---|---|---|---|
| 1/16" (62 mils) | 50–75 | 1/16" E6011 @ 35–60 | 120 V hobby |
| 1/8" (125 mils) | 100–150 | 1/8" E6011 @ 75–125 | 120 V ok, 240 V comfortable |
| 3/16" (188 mils) | 150–225 | 5/32" E6011 @ 110–165 | 240 V |
| 1/4" (250 mils) | 200–300 | 1/8" @ 90–140, multi-pass | 240 V, 180–220 A |
| 3/8"+ (375+) | 300+ | Multi-pass, preheat | Shop machine |
Amp windows from published electrode and machine-manufacturer charts (Lincoln, Miller, ESAB). Rod-diameter rule: electrode diameter ≈ half the base-metal thickness, never smaller than 1/16".
Guides
What size welder for 1/4 inch steel?
The most-searched buyer question, answered honestly: what 140 A machines can and can't do, and why 1/4" is the line between hobby and shop machines.
MIG or TIG for 16–20 ga sheet metal?
Why thin metal warps, which process controls it, and the settings that keep auto-body and ductwork panels flat.
Best beginner welder by the thickness you'll actually weld
Flip the usual advice: pick the metal first, then the machine. 120 V flux-core vs a 140 A MIG vs a 200 A TIG — where each one earns its money.
Running a welder off a generator? ↗
A 200 A stick welder draws real surge power — GeneratorSizer does the generator-side math.
TIG amps by material thickness — the 1-amp-per-mil rule, tuned
Where the classic rule breaks: aluminum conductivity, stainless, thick plate, and the tungsten and filler to pair with each range.
MIG wire speed chart — ipm settings by thickness and amperage
Stop guessing the dial: ipm windows for 0.023–0.045 wire paired with voltage, by material thickness.