Gauge to thickness conversion for steel and aluminium sheet metal in mm and inches.
A sheet metal gauge chart converts standard gauge numbers to actual thickness in millimetres and inches. Three different gauge systems are in common use: Manufacturers' Standard Gauge (steel), Brown & Sharpe Gauge (aluminium, copper, brass), and US Standard Gauge (galvanised steel). The same gauge number means different thicknesses in different systems.
For steel: 16 gauge = 1.52 mm; 20 gauge = 0.91 mm; 24 gauge = 0.61 mm. For aluminium (B&S): 16 gauge = 1.29 mm; 20 gauge = 0.81 mm. Always confirm which gauge system applies to your material before ordering.
Inputs: Specifying 18-gauge steel for a kitchen sink
Yes, the same Manufacturers' Standard Gauge applies to carbon steel, stainless steel, and most ferrous sheet metals. For non-ferrous (aluminium, copper, brass), use B&S gauge. Many modern suppliers list materials directly by thickness in mm or inches, avoiding gauge ambiguity altogether — always confirm the actual thickness when in doubt.
HVAC ductwork: 26–22 gauge galvanised steel for residential, 22–20 gauge for commercial. Metal roofing: 26–24 gauge for residential, 22–20 gauge for industrial. Auto body panels: 18–16 gauge. Heavy gauge appliance bodies: 16–14 gauge. Furniture and decorative sheet: 18–22 gauge.
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