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Sheet metal gauge to mm

Choose the gauge system of your material. The table gives the nominal thickness of every gauge.

16 gauge is 1.519 mm (0.0598 in) for uncoated steel sheet, 1.613 mm (0.0635 in) for galvanised steel, 1.588 mm (0.0625 in) for stainless steel by the US Standard Gauge and 1.291 mm (0.0508 in) for aluminium by the Brown & Sharpe gauge. The same gauge number gives a different thickness in each system.

Calculator · 05

Gauge to mm

Gauge 161.519mm
GaugeInchesMillimetres
30.23916.073
40.22425.695
50.20925.314
60.19434.935
70.17934.554
80.16444.176
90.14953.797
100.13453.416
110.11963.038
120.10462.657
130.08972.278
140.07471.897
150.06731.709
160.05981.519
170.05381.367
180.04781.214
190.04181.062
200.03590.912
210.03290.836
220.02990.759
230.02690.683
240.02390.607
250.02090.531
260.01790.455
270.01640.417
280.01490.378
290.01350.343
300.0120.305
310.01050.267
320.00970.246
330.0090.229
340.00820.208
350.00750.19
360.00670.17
370.00640.163
380.0060.152

Gauge thicknesses are nominal. Some mills quote stainless sheet by the steel gauge values, so confirm the thickness with your supplier.

CutMeter is software. Check every result before you cut or bend. The person who approves the part is responsible for its dimensions.

How the tables are made

US Standard Gauge (15 U.S.C. 206): inches = ounces per ft² / 640. Manufacturers' Standard Gauge: inches = ounces per ft² / 16 / 41.82, rounded to 4 decimals. Galvanised: as the Manufacturers' Standard Gauge with 2.5 oz/ft² added. Brown & Sharpe (American Wire Gauge, ASTM B258): inches = 0.005 x 92^((36 - n) / 39). Millimetres = inches x 25.4.

n = gauge number; ounces per ft² = the statute weight for gauge n (16 gauge = 40 oz/ft²); 41.82 = pounds per ft² of steel 1 inch thick.

The tables are computed from these definitions, not copied, so they can differ from printed tables in the last decimal. Ranges: steel and stainless 3-38, galvanised 8-31, aluminium 6-31.

Worked example

Steel sheet (Manufacturers' Standard Gauge), gauge 16.

The statute weight of 16 gauge is 40 oz/ft² = 2.5 lb/ft². 2.5 / 41.82 = 0.0598 in. 0.0598 x 25.4 = 1.519 mm.

16 gauge steel sheet = 0.0598 in = 1.519 mm.

Common gauges in four systems

Nominal thickness in mm
GaugeSteel (MSG)GalvanisedStainless (USSG)Aluminium (B&S)
103.4163.513.5722.588
113.0383.1323.1752.305
122.6572.7532.7782.053
141.8971.9941.9841.628
161.5191.6131.5881.291
181.2141.3111.271.024
200.9121.0060.9520.812
220.7590.8530.7940.644
240.6070.7010.6350.511
260.4550.5510.4760.405
280.3780.4750.3970.321

Questions about gauges

How thick is 16 gauge in mm?

1.519 mm for steel sheet, 1.613 mm for galvanised steel, 1.588 mm for stainless steel and 1.291 mm for aluminium.

How thick is 18 gauge in mm?

1.214 mm for steel sheet, 1.311 mm for galvanised steel, 1.270 mm for stainless steel and 1.024 mm for aluminium.

How thick is 14 gauge in mm?

1.897 mm for steel sheet, 1.994 mm for galvanised steel, 1.984 mm for stainless steel and 1.628 mm for aluminium.

Why does the same gauge mean different thicknesses?

Steel gauges come from a weight per square foot, while aluminium uses the Brown & Sharpe wire gauge, which is a geometric series of diameters. Always state the material with the gauge, or order in millimetres.

Does this include the British Standard Wire Gauge (SWG)?

No. The tool covers the Manufacturers' Standard Gauge, the galvanised gauge, the US Standard Gauge and the Brown & Sharpe gauge.

Sources

  1. 15 U.S.C. 206, Standard gauge for sheet and plate iron and steel law.cornell.edu
  2. Wikipedia, Sheet metal: gauge table and the 41.82 lb/ft² per inch basis (citing Machinery's Handbook, 27th ed.) en.wikipedia.org
  3. Continental Steel, galvanised sheet gauge (statute weight + 2.5 oz/ft²) continentalsteel.com
  4. American Wire Gauge, ASTM B258 definition en.wikipedia.org