For MIG welding steel, start at about 1 amp for every 0.001 in of thickness: 1/8 in steel needs about 125 A, which is 0.030 in wire at about 250 in/min and 18.5–19.5 V with C25 gas. Pick your thickness, wire and gas in the MIG welding settings chart below for your own starting settings, from Miller’s setup method and Lincoln’s wire data.
Your starting settings
Pick the steel thickness and your wire and gas. You get a starting wire speed, voltage and amps for a test bead on scrap, then tune by sound and look.
- Wire speed
- 250 in/min
- Voltage
- 18.5–19.5 V
- Amps, about
- 125 A
Starting point for 1/8 in (3.2 mm), Solid wire, C25 gas (75% argon, 25% CO2)
- Wire0.030 in (0.8 mm) (picked for this thickness)
- Gas flowAbout 30–40 CFH, set on a flowmeter
- PolarityDCEP: gun on the positive (+) terminal, ground clamp on negative (−)
- Contact tip to work3/8–1/2 in
MIG welding settings chart
Starting settings for mild steel with solid ER70S-6 wire in short-circuit transfer. Amps follow Miller’s rule of 1 amp per 0.001 in of thickness; voltages come from Lincoln’s data sheet. Your machine’s door chart comes first if it has one. Starred rows have a note under the chart.
| Steel thickness | Amps | Wire | Wire speed | Voltage, C25 | Voltage, CO2 |
|---|---|---|---|---|---|
| 24 gauge (0.024 in) * | 24 A | 0.023 in (0.6 mm) | 85 in/min | 15–16 V | 17 V |
| 22 gauge (0.030 in) | 30 A | 0.023 in (0.6 mm) | 105 in/min | 15–16 V | 17 V |
| 20 gauge (0.036 in) | 36 A | 0.023 in (0.6 mm) | 125 in/min | 15.5–16.5 V | 17.5 V |
| 18 gauge (0.048 in) | 48 A | 0.030 in (0.8 mm) | 95 in/min | 15.5–16.5 V | 17.5 V |
| 16 gauge (0.060 in) | 60 A | 0.030 in (0.8 mm) | 120 in/min | 15.5–16.5 V | 17.5 V |
| 14 gauge (0.075 in) | 75 A | 0.030 in (0.8 mm) | 150 in/min | 16–17 V | 18 V |
| 12 gauge (0.105 in) | 105 A | 0.030 in (0.8 mm) | 210 in/min | 17.5–18.5 V | 19.5 V |
| 1/8 in (3.2 mm) | 125 A | 0.030 in (0.8 mm) | 250 in/min | 18.5–19.5 V | 20.5 V |
| 10 gauge (0.135 in) | 135 A | 0.030 in (0.8 mm) | 270 in/min | 19–20 V | 21 V |
| 3/16 in (4.8 mm) | 188 A | 0.045 in (1.1 mm) | 190 in/min | 19–20 V | 21 V |
| 1/4 in (6.4 mm) * | 200 A | 0.045 in (1.1 mm) | 200 in/min | 19–20 V | 21 V |
| 5/16 in (7.9 mm) * | 200 A | 0.045 in (1.1 mm) | 200 in/min | 19–20 V | 21 V |
- * 24 gauge (0.024 in): This sheet needs less current than any MIG wire is rated for (0.023 in starts at 30 A): use 0.023 in wire at your welder’s lowest settings and test on scrap first. This wire speed is below the slowest in Lincoln’s chart for this wire, so the voltage is its lowest row. Tune it on scrap.
- * 1/4 in (6.4 mm): Lincoln’s short-circuit data for 0.045 in (1.1 mm) wire tops out at 200 in/min and about 200 A, less than one pass on this thickness needs. Weld it in several passes at these settings: on a butt joint, bevel it first; on a fillet, build up the leg size pass by pass. For heavy plate, gas-shielded flux core (E71T-1) or spray transfer suits better.
- * 5/16 in (7.9 mm): Lincoln’s short-circuit data for 0.045 in (1.1 mm) wire tops out at 200 in/min and about 200 A, less than one pass on this thickness needs. Weld it in several passes at these settings: on a butt joint, bevel it first; on a fillet, build up the leg size pass by pass. For heavy plate, gas-shielded flux core (E71T-1) or spray transfer suits better.
Gasless flux core settings chart
| Steel thickness | Wire | Wire speed | Voltage |
|---|---|---|---|
| 24 gauge (0.024 in) * | 0.030 in (0.8 mm) | 50 in/min | 13–14 V |
| 22 gauge (0.030 in) | 0.030 in (0.8 mm) | 50 in/min | 13–14 V |
| 20 gauge (0.036 in) | 0.030 in (0.8 mm) | 60 in/min | 13–14 V |
| 18 gauge (0.048 in) | 0.030 in (0.8 mm) | 80 in/min | 13–14 V |
| 16 gauge (0.060 in) | 0.035 in (0.9 mm) | 70 in/min | 15–16 V |
| 14 gauge (0.075 in) | 0.035 in (0.9 mm) | 80 in/min | 15.5–16.5 V |
| 12 gauge (0.105 in) | 0.035 in (0.9 mm) | 105 in/min | 16–17 V |
| 1/8 in (3.2 mm) | 0.035 in (0.9 mm) | 135 in/min | 16.5–17.5 V |
| 10 gauge (0.135 in) | 0.035 in (0.9 mm) | 160 in/min | 17–18 V |
| 3/16 in (4.8 mm) * | 0.045 in (1.1 mm) | 130 in/min | 18–19 V |
| 1/4 in (6.4 mm) * | 0.045 in (1.1 mm) | 130 in/min | 18–19 V |
| 5/16 in (7.9 mm) * | 0.045 in (1.1 mm) | 130 in/min | 18–19 V |
- * 24 gauge (0.024 in): This is the lowest setting in Lincoln’s data for 0.030 in (0.8 mm) gasless wire; thinner metal needs a smaller wire or short tack welds.
- * 3/16 in (4.8 mm): Lincoln’s data for 0.045 in (1.1 mm) gasless wire tops out at 130 in/min and about 170 A. One pass at these settings suits a fillet weld up to about 3/16 in; on a butt joint, bevel it and weld it in several passes.
- * 1/4 in (6.4 mm): Lincoln’s data for 0.045 in (1.1 mm) gasless wire tops out at 130 in/min and about 170 A, less than one pass on this thickness needs. Weld it in several passes at these settings: on a butt joint, bevel it first; on a fillet, build up the leg size pass by pass. Lincoln rates these small gasless wires for plate up to 5/16 in.
- * 5/16 in (7.9 mm): Lincoln’s data for 0.045 in (1.1 mm) gasless wire tops out at 130 in/min and about 170 A, less than one pass on this thickness needs. Weld it in several passes at these settings: on a butt joint, bevel it first; on a fillet, build up the leg size pass by pass. Lincoln rates these small gasless wires for plate up to 5/16 in.
Quick answers
My welder has numbered voltage taps, not volts. What do I set?
Many 120 V hobby MIG welders have numbered or lettered voltage taps instead of a volts dial. Use the chart inside the machine’s door for the tap, set the wire speed from this table, then tune by sound: a steady crackle, like bacon frying, means the two match.
What are the MIG settings for 1/8 inch steel?
1/8 in (3.2 mm): about 125 A, so 0.030 in (0.8 mm) wire at about 250 in/min and 18.5–19.5 V. That is with C25 gas; with straight CO2, start at 20.5 V.
What are the MIG settings for 16 gauge sheet metal?
16 gauge (0.060 in): about 60 A, so 0.030 in (0.8 mm) wire at about 120 in/min and 15.5–16.5 V. C25 spatters less than straight CO2, which helps on thin sheet.
What MIG settings for 1/4 inch steel?
One pass on 1/4 in steel needs about 250 A, more than short-circuit MIG covers in Lincoln’s data: for 0.045 in (1.1 mm) wire it tops out at 200 in/min and about 200 A (21 V on CO2, 19–20 V with C25). Weld it in several passes at those settings (bevel a butt joint first; build a fillet up pass by pass), or switch to gas-shielded flux core (E71T-1) or spray transfer.
How many amps do I need to MIG weld steel?
About 1 amp for every 0.001 in of thickness: 1/8 in (0.125 in) needs about 125 A, 3/16 in about 188 A and 1/4 in about 250 A.
What size MIG wire should I use?
Match the wire to the amps you weld most: 0.023 in (0.6 mm) for 30–90 A; 0.030 in (0.8 mm) for 40–145 A; 0.035 in (0.9 mm) for 50–180 A; 0.045 in (1.1 mm) for 75–250 A. 0.030 in is a good all-round size for sheet up to 1/8 in.
How do I set wire speed from amps?
Multiply the amps by the in/min per amp for your wire: 3.5 for 0.023 in (0.6 mm), 2.0 for 0.030 in (0.8 mm), 1.6 for 0.035 in (0.9 mm), 1.0 for 0.045 in (1.1 mm). At 125 A that is about 438, 250, 200, 125 in/min.
How do I know my MIG voltage is right?
Listen and look. Too low: the wire stubs into the plate, spatters and leaves a tall bead. Too high: the arc hisses, wanders and undercuts. Right: a steady buzz and a flat bead that ties into both edges.
Does CO2 need more voltage than C25?
Yes. Lincoln’s wire data gives short-circuit voltages for 100% CO2 and says to reduce them by 1 to 2 volts for 75% argon, 25% CO2.
What are the flux core welder settings for 1/8 inch?
1/8 in (3.2 mm): about 125 A, so 0.035 in (0.9 mm) wire at about 135 in/min and 16.5–17.5 V. Gasless flux core runs DCEN: the gun goes on the negative terminal.
How much gas flow for MIG welding?
About 30–40 cubic feet per hour, set on a flowmeter. More is not better: too much flow turns turbulent and pulls air into the weld.
- Amps, wire size and wire speed: Miller Electric, “MIG Welding: Setting the Correct Parameters” (2025) and the Millermatic 252 owner’s manual (OM-230693, 2026). The manual gives 30–90 A for 0.023 in wire; the article says 30–130 A.
- Voltage, current and contact tip distance: Lincoln Electric SuperArc L-56 (ER70S-6) data sheet, short-circuit procedures on 100% CO2, with its note to reduce voltage by 1 to 2 volts for C25. The 0.023 in rows use Lincoln’s 0.025 in figures.
- Gasless flux core: Lincoln Electric Innershield NR-211-MP (E71T-11) data sheet, and its limit of 5/16 in plate for 0.045 in and smaller wire.
- Gas flow and arc sound: Lincoln Electric, “GMAW: Common MIG Problems and Remedies”. Gauge thicknesses: Manufacturers’ Standard Gauge for sheet steel.
- Between two rows of Lincoln’s data the tool draws a straight line. These are starting points: run a test bead on scrap of the same thickness and tune.
Numbers checked on by Randy Williams against the sources below. Spotted a mistake? Tell us.
- Miller Electric, “MIG Welding: Setting the Correct Parameters” (2025)
- Miller Electric, Millermatic 252 owner’s manual OM-230693 (2026), “Typical GMAW (MIG) Process Control Settings”
- Lincoln Electric, SuperArc L-56 (ER70S-6) data sheet, typical operating procedures
- Lincoln Electric, Innershield NR-211-MP (E71T-11) data sheet, typical operating procedures
- Lincoln Electric, “GMAW: Common MIG Problems and Remedies”