Calculator
Welding amperage calculator
Rule-of-thumb current ranges used by Australian fabricators, tuned by process and material. Start low, watch the puddle, adjust.
Single pass, butt or fillet — heavy section may need multi-pass + prep.
How these ranges are derived
For mild steel, the trade rule of thumb is roughly 40 amps per millimetre for MIG in spray/short-arc crossover territory, ~30–40 A/mm for TIG DC, and ~35–50 A/mm for stick depending on electrode class and position. Stainless runs ~10% less current than mild steel at the same thickness (higher resistance, slower travel); aluminium on TIG AC typically needs more current per mm (higher thermal conductivity pulls heat away) — around 40–50 A/mm for hand-fed fillets.
These are starting points from common Australian practice (AS/NZS 1554 work), not a substitute for a qualified welding procedure for structural work.
Reference table — mild steel
| Thickness | MIG | TIG | Stick | Typical filler (MIG) |
|---|---|---|---|---|
| 1 mm | 40–60 A | 30–60 A | not practical | 0.6 mm |
| 1.5 mm | 60–90 A | 50–80 A | 40–60 A (2.0 mm rod) | 0.8 mm |
| 3 mm | 110–150 A | 90–130 A | 80–110 A (2.6 mm rod) | 0.9 mm |
| 6 mm | 180–240 A | 150–200 A | 120–160 A (3.2 mm rod) | 0.9–1.2 mm |
| 10 mm | 250–320 A | 220–280 A | 160–200 A (4.0 mm rod) | 1.2 mm |
| 12 mm+ | 280–380 A | multi-pass | 180–240 A (4.0–5.0 mm) | 1.2 mm, multi-pass + bevel |
Position changes things: vertical-up and overhead run 10–20% below flat-range current.