A 16-gauge part on one drawing and a 0.060" part on the next is the same piece of steel. This is the gauge-to-inch-to-millimeter table for sheet steel — the one that lives on every shop wall.
Values for plain carbon sheet steel. Galvanized and stainless sheet run within a couple of thousandths; aluminum uses its own gauge system.
| Gauge | Inches | mm | Typical Uses |
|---|---|---|---|
| 10 | 0.1345" | 3.42 | Truck floors, equipment panels |
| 11 | 0.1196" | 3.04 | Structural framing, farm equipment |
| 12 | 0.1046" | 2.66 | Trailer frames, heavy toolboxes |
| 13 | 0.0897" | 2.28 | Machine guards, light structural |
| 14 | 0.0747" | 1.90 | Auto floorpans, light framing |
| 15 | 0.0673" | 1.71 | General fabrication |
| 16 | 0.0598" | 1.52 | Car panels, toolboxes, HVAC plenums |
| 17 | 0.0538" | 1.37 | Light auto panels |
| 18 | 0.0478" | 1.21 | Car doors, hoods, shelving |
| 19 | 0.0418" | 1.06 | Appliances, lighter panels |
| 20 | 0.0359" | 0.91 | Car bodies, appliance shells |
| 21 | 0.0329" | 0.84 | Lighter bodies, guards |
| 22 | 0.0299" | 0.76 | HVAC ducting, lighting |
| 23 | 0.0269" | 0.68 | HVAC fittings |
| 24 | 0.0239" | 0.61 | HVAC duct, gutters |
| 25 | 0.0209" | 0.53 | Light duct, flashings |
| 26 | 0.0179" | 0.45 | Roofing, flashing |
The gauges that actually show up when someone says "that's an eighth-inch part".
| Fraction | Decimal | Nearest Gauge |
|---|---|---|
| 1/16" | 0.0625" | 16 ga (0.0598") |
| 3/32" | 0.0938" | 13 ga (0.0897") |
| 1/8" | 0.1250" | 11 ga (0.1196") |
| 3/16" | 0.1875" | 7 ga (0.1873") |
| 1/4" | 0.2500" | 3 ga (0.2501") |
1 inch = 25.4 mm. Multiply inches × 25.4 for mm; divide mm by 25.4 for inches.
Gauge matters more than any other number when the part is thin. These are the short-circuit GMAW starting points for ER70S-6 on 75/25 gas.
| Gauge | Amps | Voltage | Wire | Wire Feed |
|---|---|---|---|---|
| 26–24 ga | 30–50 A | 13–15 V | 0.023" | 90–140 IPM |
| 22–20 ga | 40–60 A | 14–16 V | 0.023"–0.030" | 120–180 IPM |
| 18 ga | 60–80 A | 15–17 V | 0.030" | 150–210 IPM |
| 16 ga | 80–100 A | 16–18 V | 0.030" | 170–240 IPM |
| 14 ga | 95–120 A | 17–19 V | 0.030"–0.035" | 190–260 IPM |
| 12–11 ga | 110–150 A | 18–20 V | 0.035" | 220–300 IPM |
Thin sheet moves with every bead. Tack every 2–3 inches on long seams and let it cool between tacks.
Short-circuit MIG on 22 ga and thinner works best as short bursts — trigger in and out — to keep total heat down.
A copper backup bar under thin butt joints soaks heat and prevents blow-through better than any setting change.
Use your calculated requirements to get an equipment recommendation for your application.
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