Welding Amperage Chart — SMAW, GMAW, GTAW, FCAW
Starting amperage settings for stick (SMAW), MIG (GMAW), TIG (GTAW), and flux-core (FCAW) welding by electrode size, material, and material thickness. Includes voltage, wire-feed speed, and travel speed where applicable.
Reference
Starting amperage / voltage values by process. These are starting points — adjust ±10-15% based on bead appearance, penetration, and travel speed. Rule of thumb: 1 amp per 0.001" of plate thickness for steel (mild rule, breaks down outside 1/16"-1/2"). Always test on scrap of the same thickness before production work.
SMAW (Stick / Arc) — mild steel
| Electrode Ø | Material thickness | 6010 / 6011 (DC+ / AC) | 6013 (AC / DC±) | 7018 (DC+ / AC) | 7024 (AC / DC±) |
|---|---|---|---|---|---|
| 1/16" (1.6 mm) | < 1/16" (light gauge) | 20-40 A | 20-45 A | — | — |
| 5/64" (2.0 mm) | 1/16" - 1/8" | 40-65 A | 35-60 A | — | — |
| 3/32" (2.4 mm) | 1/8" - 3/16" | 40-90 A | 40-90 A | 70-100 A | 70-110 A |
| 1/8" (3.2 mm) | 3/16" - 1/4" | 70-130 A | 80-130 A | 110-160 A | 120-180 A |
| 5/32" (4.0 mm) | 1/4" - 3/8" | 120-160 A | 120-180 A | 150-200 A | 170-240 A |
| 3/16" (4.8 mm) | 3/8" - 1/2" | 140-200 A | 160-220 A | 180-260 A | 210-300 A |
| 7/32" (5.6 mm) | 1/2" - 5/8" | 180-240 A | 180-260 A | 230-310 A | 250-340 A |
| 1/4" (6.4 mm) | > 5/8" | 220-310 A | 220-300 A | 270-380 A | 300-420 A |
| 5/16" (8.0 mm) | > 3/4" (heavy) | 270-360 A | — | 330-450 A | 370-520 A |
SMAW — stainless and alloy electrodes
| Electrode Ø | 308L / 309L / 316L (DC+ / AC) | 7014 (AC / DC+) | 11018 / 12018 (DC+ / AC) |
|---|---|---|---|
| 3/32" (2.4 mm) | 40-80 A | 60-100 A | 90-130 A |
| 1/8" (3.2 mm) | 70-115 A | 100-150 A | 130-180 A |
| 5/32" (4.0 mm) | 95-150 A | 140-200 A | 170-230 A |
| 3/16" (4.8 mm) | 120-200 A | 180-240 A | 210-300 A |
GMAW (MIG) — mild / low-alloy steel, short-circuit transfer
| Wire Ø | Thickness | Wire feed (IPM) | Voltage (V) | Amperage (A) | Travel speed (IPM) |
|---|---|---|---|---|---|
| 0.023" (0.6 mm) | 24-22 ga (0.024-0.030") | 85-150 | 14-15 | 40-55 | 12-18 |
| 0.023" (0.6 mm) | 20-18 ga (0.036-0.048") | 150-220 | 15-16 | 55-90 | 14-20 |
| 0.030" (0.8 mm) | 18-16 ga (0.048-0.060") | 180-280 | 16-17 | 90-130 | 14-22 |
| 0.030" (0.8 mm) | 14-11 ga (0.075-0.120") | 240-350 | 17-18 | 130-180 | 12-20 |
| 0.035" (0.9 mm) | 11 ga - 1/4" (0.120-0.250") | 230-380 | 17-19 | 140-220 | 12-18 |
| 0.035" (0.9 mm) | 1/4" - 3/8" | 300-420 | 18-20 | 180-260 | 10-14 |
| 0.045" (1.2 mm) | 1/4" - 1/2" | 230-370 | 19-22 | 200-300 | 10-15 |
| 0.045" (1.2 mm) | > 1/2" | 280-450 | 21-25 | 260-380 | 8-12 |
| 0.052" (1.3 mm) | 3/8" - 3/4" | 230-380 | 23-28 | 300-420 | 8-12 |
GMAW (MIG) — spray transfer (open root, position 1G/1F only)
| Wire Ø | Voltage | Amperage | Wire feed | Notes |
|---|---|---|---|---|
| 0.035" (0.9 mm) | 24-30 V | 180-280 A | 380-650 IPM | Min ~85% Argon shielding for stable spray |
| 0.045" (1.2 mm) | 26-32 V | 250-380 A | 300-560 IPM | Standard production wire |
| 0.052" (1.3 mm) | 28-34 V | 280-450 A | 270-470 IPM | Heavy plate |
| 1/16" (1.6 mm) | 30-36 V | 350-550 A | 180-380 IPM | Heavy plate; high deposition |
GMAW — aluminum (4043 / 5356 wire, 100% Argon, push gun)
| Wire Ø | Thickness | Voltage | Amperage | Wire feed (IPM) |
|---|---|---|---|---|
| 0.030" (0.8 mm) | 0.040" - 1/8" | 15-18 V | 60-110 A | 180-300 |
| 0.035" (0.9 mm) | 1/16" - 3/16" | 16-20 V | 90-150 A | 180-380 |
| 3/64" (1.2 mm) | 1/8" - 3/8" | 18-26 V | 120-220 A | 200-460 |
| 1/16" (1.6 mm) | 3/16" - 1/2" | 21-30 V | 180-320 A | 160-420 |
| 3/32" (2.4 mm) | 3/8" - 3/4" | 23-32 V | 270-450 A | 120-340 |
GTAW (TIG) — DCEN (negative, for steel / stainless / titanium)
| Tungsten Ø | Steel thickness | Amperage | Filler rod Ø | Argon CFH |
|---|---|---|---|---|
| 0.040" (1.0 mm) | < 0.040" | 5-25 A | 0.020"-0.040" | 8-10 |
| 1/16" (1.6 mm) | 0.040" - 1/16" | 30-90 A | 1/16" | 10-15 |
| 3/32" (2.4 mm) | 1/16" - 1/8" | 70-160 A | 1/16" - 3/32" | 10-20 |
| 1/8" (3.2 mm) | 1/8" - 3/16" | 120-240 A | 3/32" - 1/8" | 15-25 |
| 5/32" (4.0 mm) | 3/16" - 1/4" | 200-330 A | 1/8" - 5/32" | 15-25 |
| 3/16" (4.8 mm) | 1/4" - 3/8" | 300-420 A | 1/8" - 3/16" | 20-30 |
| 1/4" (6.4 mm) | > 3/8" | 400-525 A | 3/16" - 1/4" | 25-35 |
GTAW (TIG) — AC (aluminum / magnesium)
| Tungsten Ø | Aluminum thickness | Amperage | Filler 4043 | Argon CFH |
|---|---|---|---|---|
| 1/16" (1.6 mm) | 0.040" - 1/16" | 30-80 A | 1/16" | 15 |
| 3/32" (2.4 mm) | 1/16" - 1/8" | 60-150 A | 1/16" - 3/32" | 15-20 |
| 1/8" (3.2 mm) | 1/8" - 3/16" | 120-220 A | 3/32" - 1/8" | 17-25 |
| 5/32" (4.0 mm) | 3/16" - 1/4" | 180-300 A | 1/8" | 20-30 |
| 3/16" (4.8 mm) | 1/4" - 3/8" | 240-380 A | 1/8" - 3/16" | 25-35 |
| 1/4" (6.4 mm) | > 3/8" | 350-525 A | 3/16" - 1/4" | 30-40 |
FCAW (Flux-Core) — self-shielded (gasless) and dual-shield
| Wire Ø | Process | Thickness | Voltage | Amperage | Wire feed |
|---|---|---|---|---|---|
| 0.030" (0.8 mm) | Self-shield (E71T-GS) | 20 ga - 1/8" | 14-19 V | 60-150 A | 60-260 IPM |
| 0.035" (0.9 mm) | Self-shield (E71T-11) | 18 ga - 3/16" | 15-21 V | 90-200 A | 70-300 IPM |
| 0.045" (1.2 mm) | Self-shield (E71T-11) | 14 ga - 1/4" | 17-22 V | 120-280 A | 60-260 IPM |
| 0.052" (1.3 mm) | Dual-shield (E71T-1) | 1/8" - 1/2" | 24-30 V | 200-450 A | 160-400 IPM |
| 1/16" (1.6 mm) | Dual-shield (E71T-1) | 3/16" - 3/4" | 26-34 V | 280-550 A | 120-350 IPM |
| 3/32" (2.4 mm) | Dual-shield (E71T-1) | 1/4" - 1"+ | 28-38 V | 350-650 A | 90-260 IPM |
Quick formula — amps from thickness
- Mild steel rule of thumb
- A = 1 × thickness in thousandths. 1/8" = 0.125" = 125 thou → ~125 A starting point.
- Aluminum
- A ≈ 1.0 × thou for thin, drops to 0.7-0.8 × thou for heavy due to back-conduction. 1/4" Al = ~180-200 A AC.
- Stainless
- A ≈ 0.7 × thou — runs ~30% lower than mild steel due to lower thermal conductivity.
- Volts (MIG)
- V ≈ 14 + (0.04 × A) for short-circuit. 150 A → 20 V starting point.
- Stickout
- MIG: keep stickout 3/8" - 5/8" of wire diameter. Long stickout = more amperage drop.
Bead-reading guide
| Symptom | Likely cause | Adjustment |
|---|---|---|
| Tall narrow ropy bead | Voltage too low, amperage too high, travel too slow | Increase volts; speed up travel |
| Wide flat bead, lots of spatter | Voltage too high, amperage too low, travel too fast | Drop volts; slow down |
| No penetration / cold lap | Amps too low, travel too fast | Increase amps OR slow travel |
| Burn-through on thin material | Amps too high, travel too slow | Drop amps OR speed up |
| Porosity (pinholes) | Gas flow / drafts / dirty base / contaminated wire | Check gas flow 15-25 CFH; clean joint; new wire |
| Excessive spatter (MIG) | Voltage too low for amperage | Match V/A or increase voltage |
| Undercut (groove along bead toe) | Travel too fast, amps too high, bad gun angle | Slow down; reduce amps; lay flatter |
| Convex bead (humped) on stick | Travel too slow, polarity wrong | Speed up; check DC+ vs DC− for electrode |
Polarity reference
- DCEP / DC+ / Reverse
- Electrode positive: deeper penetration, smoother arc. Use for 7018, 7024, MIG / FCAW with most wires.
- DCEN / DC− / Straight
- Electrode negative: less penetration, faster melt-off. Use for 6013 light gauge, GTAW (TIG) on steel.
- AC
- Alternating: TIG aluminum (cleaning + penetration), some 6011 / 6013 stick on AC welders.
- Square-wave AC
- Modern TIG inverters; adjustable EN/EP balance. 70/30 EN/EP standard for aluminum.
Notes
- Starting values from AWS D1.1 / Lincoln Electric Procedure Handbook / Miller Welding Handbook. Always test on scrap and verify against your machine and procedure.
- For aluminum or stainless work above 3/8" thickness, consider preheating (250-400°F for stainless to prevent carbide precipitation; 200-300°F for thick aluminum to drive moisture).
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