Sheet Metal Gauge Chart

Sheet Metal Gauge Chart: 18 Gauge Thickness in MM

When working with sheet metal, the term “gauge” refers to the material’s thickness or thickness range. However, persons unfamiliar with the gauge system may struggle to understand what a given gauge, such as 18 gauge steel, means. To clarify, this blog will explain the gauge system and provide a useful sheet metal gauge chart.

The gauge system is a standardized way for measuring and categorizing the thickness of sheet metal. It assigns numerical values to varying thicknesses, with larger gauge numbers indicating thinner sheets. For example, 18 gauge steel is thicker than 22 gauge steel. If you need precise measurements, the 18 gauge thickness in mm can help you establish the actual size of the material, and translating 18 gauge to mm gives you a clear reference for manufacture and design.

The blog will include a sheet metal gauge chart to help you visualize and comprehend the various gauges and accompanying thicknesses. This chart will show the gauge numbers and the associated thickness in inches or millimeters, making it easy to understand the measurements of various gauges.

Readers will have a better grasp of how to interpret and deal with sheet metal of varied thicknesses after being given an explanation of the gauge system and shown a sheet metal gauge chart. Knowing the 18 gauge thickness in millimeters is very useful for anyone working in industries like manufacturing, construction, or metal fabrication, where working with sheet metal is frequent.

How are Sheet Metal Gauges Used?

Gauges are used to define the thickness of sheet metal, however they are neither standardised or based on standard or metric measurements. The gauge values are independent and do not have a direct relationship to specific measurements. A gauge conversion chart is used to determine the exact thickness of sheet metal in inches or millimeters.

This chart shows the corresponding thickness values for each gauge. According to a gauge conversion chart, 18 gauge thickness in mm equals roughly 1.214 millimetres (0.0478 inches). Understanding 18 gauge to mm conversion aids in accurate measurements while working with various sheet metals. It is vital to note that the gauge number is unrelated to the actual measurements.

Different gauge systems are used for various metal kinds. For example, under one gauge system, 18 gauge steel is 0.0478 inches thick, whereas 18 gauge aluminum is 0.0403 inches thick. These variances underscore the significance of consulting to a gauge chart to confirm that the metal satisfies the specifications.

Using a gauge conversion chart, anyone may precisely determine the thickness of sheet metal, regardless of the gauge system or metal type utilized. This information is useful in a variety of industries, including manufacturing, building, and metal fabrication, where exact measurements are required for successful operations.

History of the Gauge System

The gauge system is a historic method for measuring metal thickness, with origins in the British wire industry. Originally, it was intended to define the diameter of drawn metal wires before standardized and metric measurement methods became widely used. Over time, this technique became extensively used for both wire and sheet metal, providing a convenient way to specify material thickness.

Although modern electrical cables are frequently measured by their cross-sectional area in square millimetres, the standard wire gauge (SWG) is still widely used for sheet metal. When working with sheet metal, thickness can be reliably measured with equipment such as callipers or ultrasonic gauges, which generally come with reference charts unique to the metal being utilized.

Sheet Metal Gauge Charts

Mild Steel Gauge Chart
GaugeNumber	Inches	MM
7	.1793	4.554
8	.1644	4.175
9	.1495	3.797
10	.1345	3.416
11	.1196	3.038
12	.1046	2.656
14	.0747	1.897
16	.0598	1.518
18	.0478	1.214
20	.0359	.911
22	.0299	.759
24	.0239	.607
26	.0179	.454
28	.0149	.378

Aluminum Gauge Chart*
GaugeNumber	Inches	MM
7	.1443	3.665
8	.1285	3.264
9	.1144	2.906
10	.1019	2.588
11	.09074	2.305
12	.08081	2.053
14	.06408	1.628
16	.05082	1.291
18	.04030	1.024
20	.03196	.812
22	.02535	.644
24	.02010	.511
26	.01594	.405
28	.01264	.321
30	.01003	.255

Stainless Steel Gauge Chart*
GaugeNumber	Inches	MM
8	.17187	4.365
9	.15625	3.968
10	.14062	3.571
11	.125	3.175
12	.10937	2.778
14	.07812	1.984
16	.0625	1.587
18	.050	1.270
20	.0375	.9525
22	.03125	.7937
24	.025	.635
26	.01875	.476
28	.01562	.396
30	.0125	.3175

Galvanized Steel Gauge Chart*
GaugeNumber	Inches	MM
8	.1681	4.269
9	.1532	3.891
10	.1382	3.510
11	.1233	3.1318
12	.1084	2.753
14	.0785	1.9939
16	.0635	1.6129
18	.0516	1.310
20	.0396	1.005
22	.0336	.853
24	.0276	.701
26	.0217	.551
28	.0187	.474
30	.0157	.398

Brass Gauge Chart*
GaugeNumber	Inches	MM
7	.1443	3.665
8	.1285	3.264
9	.1144	2.906
10	.1019	2.588
11	.09074	2.305
12	.08081	2.053
14	.06408	1.628
16	.05082	1.291
18	.04030	1.024
20	.03196	.812
22	.02535	.644
24	.02010	.511
26	.01594	.405
28	.01264	.321
30	.01003	.255

Copper Gauge Chart*
GaugeNumber	Inches	MM
7	.180	4.572
8	.165	4.191
9	.148	3.759
10	.134	3.404
11	.120	3.048
12	.109	2.769
14	.083	2.108
16	.065	1.651
18	.049	1.245
20	.035	.889
22	.028	.711
24	.022	.559
26	.018	.457
28	.014	.356
30	.012	.305

GAUGE CHART

GAUGE #	BRASS & ALUMINUM SHEETS		COLD & HOT ROLLED STEEL SHEETS		ALU., COPPER, BRASS,& STEEL TUBES COPPER SHEETS HOOP STEEL		STAINLESS STEEL SHEETS		GALVANIZED STEEL SHEETS
	INCHES	MM	INCHES	MM	INCHES	MM	INCHES	MM	INCHES	MM
7	1443	3.665	0.1793	4.554	0.180	4.572
8	0.1285	3.264	0.1644	4.175	0.165	4.191	0.17187	4.365	0.1681	4.269
9	0.1144	2.906	0.1495	3.797	0.148	3.759	0.15625	3.968	0.1532	3.891
10	0.1019	2.588	0.1345	3.416	0.134	3.404	0.14062	3.571	0.1382	3.510
11	0.09074	2.305	0.1196	3.038	0.120	3.048	0.125	3.175	0.1233	3.1318
12	0.08081	2.053	0.1046	2.656	0.109	2.769	0.10937	2.778	0.1084	2.753
14	0.06408	1.628	0.0747	1.897	0.083	2.108	0.07812	1.984	0.0785	1.9939
16	0.05082	1.291	0.0598	1.518	0.065	1.651	0.0625	1.587	0.0635	1.6129
18	0.04030	1.024	0.0478	1.214	0.049	1.245	0.050	1.270	0.0516	1.310
20	0.03196	0.812	0.0359	0.911	0.035	0.889	0.0375	0.9525	0.0396	1.005
22	0.02535	0.644	0.0299	0.759	0.028	0.711	0.03125	0.7937	0.0336	0.853
24	0.02010	0.511	0.0239	0.607	0.022	0.559	0.025	0.635	0.0276	0.701
26	0.01594	0.405	0.0179	0.454	0.018	0.457	0.01875	0.476	0.0217	0.551
28	0.01264	0.321	0.0149	0.378	0.014	0.356	0.01562	0.396	0.0187	0.474
30	0.01003	0.255	0.0120	0.305	0.012	0.305	0.0125	0.3175	0.0157	0.398

Standard Steel Gauge Chart

Gauge	Thickness (in)	Thickness (mm)	Weight (lb/ft²)	Weight (kg/m²)
3	0.2391	6.073	9.754	47.624
4	0.2242	5.695	9.146	44.656
5	0.2092	5.314	8.534	41.668
6	0.1943	4.935	7.927	38.701
7	0.1793	4.554	7.315	35.713
8	0.1644	4.176	6.707	32.745
9	0.1495	3.797	6.099	29.777
10	0.1345	3.416	5.487	26.790
11	0.1196	3.038	4.879	23.822
12	0.1046	2.657	4.267	20.834
13	0.0897	2.278	3.659	17.866
14	0.0747	1.897	3.047	14.879
15	0.0673	1.709	2.746	13.405
16	0.0598	1.519	2.440	11.911
17	0.0538	1.367	2.195	10.716
18	0.0478	1.214	1.950	9.521
19	0.0418	1.062	1.705	8.326
20	0.0359	0.912	1.465	7.151
21	0.0329	0.836	1.342	6.553
22	0.0299	0.759	1.220	5.955
23	0.0269	0.683	1.097	5.358
24	0.0239	0.607	0.975	4.760
25	0.0209	0.531	0.853	4.163
26	0.0179	0.455	0.730	3.565
27	0.0164	0.417	0.669	3.267
28	0.0149	0.378	0.608	2.968
29	0.0135	0.343	0.551	2.689
30	0.0120	0.305	0.490	2.390
31	0.0105	0.267	0.428	2.091
32	0.0097	0.246	0.396	1.932
33	0.0090	0.229	0.367	1.793
34	0.0082	0.208	0.335	1.633
35	0.0075	0.191	0.306	1.494
36	0.0067	0.170	0.273	1.335
37	0.0064	0.163	0.261	1.275
38	0.0060	0.152	0.245	1.195

Zinc Gauge Chart

Gauge	Thickness (in)	Thickness (mm)	Weight (lb/ft²)	Weight (kg/m²)
28	1.0000	25.400	37.152	181.392
27	0.5000	12.700	18.576	90.696
26	0.3750	9.525	13.932	68.022
25	0.2500	6.350	9.288	45.348
24	0.1250	3.175	4.644	22.674
23	0.1000	2.540	3.715	18.139
22	0.0900	2.286	3.344	16.325
21	0.0800	2.032	2.972	14.511
20	0.0700	1.778	2.601	12.697
19	0.0600	1.524	2.229	10.884
18	0.0550	1.397	2.043	9.977
17	0.0500	1.270	1.858	9.070
16	0.0450	1.143	1.672	8.163
15	0.0400	1.016	1.486	7.256
14	0.0360	0.914	1.337	6.530
13	0.0320	0.813	1.189	5.805
12	0.0280	0.711	1.040	5.079
11	0.0240	0.610	0.892	4.353
10	0.0200	0.508	0.743	3.628
9	0.0180	0.457	0.669	3.265
8	0.0160	0.406	0.594	2.902
7	0.0140	0.356	0.520	2.539
6	0.0120	0.305	0.446	2.177
5	0.0100	0.254	0.372	1.814
4	0.0080	0.203	0.297	1.451
3	0.0060	0.152	0.223	1.088
2	0.0040	0.102	0.149	0.726
1	0.0020	0.051	0.074	0.363

Birmingham Gage (BG) Chart

Gauge	Thickness (in)	Thickness (mm)
0000000	0.6666	16.932
000000	0.6250	15.875
00000	0.5883	14.943
0000	0.5416	13.757
000	0.5000	12.700
00	0.4452	11.308
0	0.3964	10.069
1	0.3532	8.971
2	0.3147	7.993
3	0.2804	7.122
4	0.2500	6.350
5	0.2225	5.652
6	0.1981	5.032
7	0.1764	4.481
8	0.1570	3.988
9	0.1398	3.551
10	0.1250	3.175
11	0.1113	2.827
12	0.0991	2.517
13	0.0882	2.240
14	0.0785	1.994
15	0.0699	1.775
16	0.0625	1.588
17	0.0556	1.412
18	0.0495	1.257
19	0.0440	1.118
20	0.0392	0.996
21	0.0349	0.886
22	0.0312	0.792
23	0.0278	0.706
24	0.0247	0.627
25	0.0220	0.559
26	0.0196	0.498
27	0.0174	0.442
28	0.0156	0.396
29	0.0139	0.353
30	0.0123	0.312
31	0.0110	0.279
32	0.0098	0.249
33	0.0087	0.221
34	0.0077	0.196
35	0.0069	0.175
36	0.0061	0.155
37	0.0054	0.137
38	0.0048	0.122
39	0.0043	0.109
40	0.0038	0.097
41	0.0034	0.086
42	0.0030	0.076
43	0.0027	0.069
44	0.0024	0.061
45	0.0021	0.053
46	0.0019	0.048
47	0.0017	0.043
48	0.0016	0.041
49	0.0013	0.033
50	0.0012	0.030
51	0.0011	0.027
52	0.0010	0.024

Common Types of Sheet Metal to Consider

Choosing the right sheet metal type is the first step toward determining the correct gauge and ensuring project success. The following are some of the most prevalent sheet metals used in industry, architecture, and manufactured goods:

Zinc-plated steel: Zinc-coated steel provides corrosion prevention. Ideal for outdoor and/or damp settings (agricultural, solar mounting, automotive components, construction frames).

Stainless Steel: Stainless steel is made with at least 10.5% chromium to resist corrosion. Ideal for hygienic applications, medical equipment, architectural designs, and food-grade applications.

Aluminum: A lightweight and corrosion-resistant metal. It is widely utilized in aerospace, automotive, facades, food packaging, and other manufactured items.

Brass: A copper-zinc alloy recognized for its beautiful look and acoustic qualities. It is widely utilized in musical instruments, construction, plumbing, and electrical hookups.

Copper: A malleable metal with excellent conducting qualities. Common applications include electrical systems, plumbing, roofing and siding, industrial gear, and electronics.

Conclusion

Finally, the gauge method has been used in the metal manufacturing business for many years. It came from the British wire industry and was originally used to define the diameter of metal wires being drawn. It gradually expanded to include the thickness of sheet metal.

The gauge system is still widely used today, despite the advent of standard and metric measurement systems. It provides a simple and widely acknowledged technique of determining sheet metal thickness, enabling for effective industry communication.

Although gauge values are unaffected by standard or metric measurements, conversion charts are available to calculate the actual thickness in inches or millimeters. This ensures accuracy and consistency when working with sheet metal of different gauges.

Overall, the gauge system’s historical significance, universal acceptability, and practicality have helped to ensure its continued use in metal manufacture. It is an invaluable tool for experts in industries such as manufacturing, construction, and metal fabrication, allowing for better communication and precise measurements to ensure project success.

Newzel Industries

Newzel Industries stocks and supplies a diverse range of carbon steel, stainless steel, alloy steel, nickel alloy steel, and special metals. Our inventory includes a variety of shapes and forms, including sheets, plates, tubes, pipes, bars, and fittings, all designed to fulfill a wide range of industrial uses.