Sheet Metal Gauge Sizes Chart (gauge/inch/mm conversion)

In the imperial and metric systems, I believe you must be very familiar with one of them.

When we express the thickness of sheet metal, especially the thickness of the galvanized sheet, people who are accustomed to using metric systems will use mm as the unit, while those who are accustomed to the imperial system will use inch as the unit.

However, do you know the difference between metric and imperial?

Let’s take a brief look.

Metric vs. Imperial

Imperial

It is a measurement system used by English-speaking countries such as the United Kingdom and the United States. Because of various historical reasons, the English system is quite complicated.

In terms of use, the imperial unit is generally been used in daily life.

But British law stipulates that commercial retail must use the metric system.

In the field of science, the British are used to the metric system, and the Americans are used to the English system.

Metric

An international weights and measures system introduced to China after the signing of the Sino-French Business Charter in 1858.

Founded in France.

On April 7, 1795, the French National Assembly decided to promulgate the metric system regulations.

After 1840, the number of countries using the metric system gradually increased.

In 1875, 17 countries signed the metric system convention in Paris, which came into force on January 1, 1876.

Difference: Metric units are measured in millimeters, and imperial units are measured in inches.

Through the above explanations, we know the metric and imperial systems already. In the field of metal processing, for a variety of reasons, some people need to know how they are converted.

For example, an American wants to confirm the required bending force according to the thickness of the sheet metal and the length of the bend, and then buy a press brake machine from China. He must first know how to express the thickness and length of the sheet metal in the metric system, and then the press brake manufacturers are able to calculate the press brake tonnage based on these data.

Brief Introduction of Gauge

Gauge Definition

First, let’s take a look at the gauge meaning.

Ga., an abbreviation for GAUGE, is a length measurement unit for diameters originating in North America and belongs to the Browne & Sharpe metering system.

Originally used in the field of medicine and jewelry.

The larger the number, the smaller the diameter.

It was later promoted and used to indicate thickness.

However, when the non-ferrous metal plate and the steel plate are in the same gauge, the thickness is actually different.

The values of the plates and pipes of the same Ga. are also different.

For example, 16Ga. corresponds to:

• The standard steel thickness is 0.0598 inches;
• The corresponding galvanized steel thickness is 0.0635 inches
• Corresponding aluminum thickness is 0.0508 inches

Gauge, inch and mm conversion table

1 gauge = 1/100 mil = 1/100,000 inch = 25.4/100000 millimetre = 0.254 micrometre

Sheet Metal Gauge Thickness Chart

In order to help you guys who specialized in metalworking industry to check sheet metal gauge to inch and sheet metal gauge to mm, I collect the sheet metal gauge sizes conversion chart (with inch and mm unit) to help you quickly find the sheet metal gauge thickness which including mild steel gauge thickness, aluminum gauge thickness, galvanized sheet gauge thickness, stainless steel gauge thickness.

You can also find the mm to gauge conversion for sheet metal by the chart provided below.

Therefore, there is no need to calculate by yourself according to the gauge to mm conversion formula.

Gauge	Galv. Steel		Stainless Steel
in/mm	in	mm	in	mm
3	–	–	0.25	6.35
4	–	–	0.2344	5.9538
5	–	–	0.2187	5.555
6	–	–	0.2031	5.1587
7	–	–	0.1875	4.7625
8	0.168	4.2672	0.1719	4.3663
9	0.1532	3.8913	0.1562	3.9675
10	0.1382	3.5103	0.1406	3.5712
11	0.1233	3.1318	0.125	3.175
12	0.1084	2.7534	0.1094	2.7788
13	0.0934	2.3724	0.0937	2.38
14	0.0785	1.9939	0.0781	1.9837
15	0.071	1.8034	0.0703	1.7856
16	0.0635	1.6129	0.0625	1.5875
17	0.0575	1.4605	0.0562	1.4275
18	0.0516	1.3106	0.05	1.27
19	0.0456	1.1582	0.0437	1.11
20	0.0396	1.0058	0.0375	0.9525
21	0.0366	0.9296	0.0344	0.8738
22	0.0336	0.8534	0.0312	0.7925
23	0.0306	0.7772	0.0281	0.7137
24	0.0276	0.701	0.025	0.635
25	0.0247	0.6274	0.0219	0.5563
26	0.0217	0.5512	0.0187	0.475
27	0.0202	0.5131	0.0172	0.4369
28	0.0187	0.475	0.0156	0.3962
29	0.0172	0.4369	0.0141	0.3581
30	0.0157	0.3988	0.0125	0.3175
31	0.0142	0.3607	0.0109	0.2769
32	0.0134	0.3404	0.0102	0.2591
33	–	–	0.0094	0.2388
34	–	–	0.0086	0.2184
35	–	–	0.0078	0.1981
36	–	–	0.007	0.1778

Gauge	Mild Steel		Aluminum
in/mm	in	mm	in	mm
3	0.2391	6.0731	0.2294	5.8268
4	0.2242	5.6947	0.2043	5.1892
5	0.2092	5.3137	0.1819	4.6203
6	0.1943	4.9352	0.162	4.1148
7	0.1793	4.5542	0.1443	3.6652
8	0.1644	4.1758	0.1285	3.2639
9	0.1495	3.7973	0.1144	2.9058
10	0.1345	3.4163	0.1019	2.5883
11	0.1196	3.0378	0.0907	2.3038
12	0.1046	2.6568	0.0808	2.0523
13	0.0897	2.2784	0.072	1.8288
14	0.0747	1.8974	0.0641	1.6281
15	0.0673	1.7094	0.0571	1.4503
16	0.0598	1.5189	0.0508	1.2903
17	0.0538	1.3665	0.0453	1.1506
18	0.0478	1.2141	0.0403	1.0236
19	0.0418	1.0617	0.0359	0.9119
20	0.0359	0.9119	0.032	0.8128
21	0.0329	0.8357	0.0285	0.7239
22	0.0299	0.7595	0.0253	0.6426
23	0.0269	0.6833	0.0226	0.574
24	0.0239	0.6071	0.0201	0.5105
25	0.0209	0.5309	0.0179	0.4547
26	0.0179	0.4547	0.0159	0.4039
27	0.0164	0.4166	0.0142	0.3607
28	0.0149	0.3785	0.0126	0.32
29	0.0135	0.3429	0.0113	0.287
30	0.012	0.3048	0.01	0.254
31	0.0105	0.2667	0.0089	0.2261
32	0.0097	0.2464	0.008	0.2032
33	0.009	0.2286	0.0071	0.1803
34	0.0082	0.2083	0.0063	0.16
35	0.0075	0.1905	0.0056	0.1422
36	0.0067	0.1702	–	–

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