BWG AND SWG TUBE CHARTS


BWG and SWG are alternative measurement systems used to define the wall thickness of a tube. BWG stands for “Birmingham Wire Gauge” (which is also called “Stubs Iron Wire Gauge”). Each BWG number (example from 10 to 22) represents a specific tube thickness, which can be converted in inches or mm. SWG stands for “Standard Wire Gauge” (also called “Imperial Wire Size”)  and is an alternative way – to BWG – to indicate the wall thickness of tubes. These measured are recalled by the ASTM A450 specification (“Standard Specification for General Requirements for Carbon and Low Alloy Steel Tubes”).


BIRMINGHAM WIRE GAUGE (BWG)

BWG Tube OD, wall thickness and weight in lbs/ft – kg/m (ASTM A450)

 

Tube Outside Diameter

22 20 18 16 14 12 11 10

inch

.028

mm

.028

inch

.035

mm 0.889 inch 0.49 mm 1.244 inch 0.65 mm 1.65 inch 0.83 mm 2.108 inch 0.109 mm 2.768 inch 0.12 mm 3.047 inch 0.134 mm 3.403
inch mm lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m
1/4″ 6.350 0.820 0.122 0.107 0.159 0.130 0.194
5/16″ 7.950 0.106 0.157 0.14 0.209 0.175 0.260
3/8″ 9.525 0.129 0.192 0.173 0.258 0.219 0.326 0.263 0.392
1/2″ 12.700 0.143 0.213 0.177 0.263 0.240 0.357 0.307 0.457 0.376 0.559 0.362 0.668 0.495 0.737
5/8″ 15.875 0.181 0.270 0.224 0.334 0.306 0.456 0.395 0.558 0.489 0.727 0.61 0.908 0.658 0.979
3/4′ 19.050 0.271 0.404 0.373 0.555 0.483 0.719 0.601 0.894 0.759 1.13 0.82 1.22 0.894 1.33
7/8″ 22.225 0.257 0.383 0.319 0.475 0.439 0.654 0.572 0.851 0.712 1.06 0.907 1.35 0.981 1.46 1.08 1.6
1″ 25.400 0.296 0.44 0.367 0.546 0.505 0.752 0.66 0.982 0.826 1.23 1.06 1.57 1.15 1.71 1.26 1.87
1-1/4″ 31.750 0.372 0.553 0.462 0.687 0.638 0.95 0.833 1.24 1.06 1.57 1.35 2.01 1.47 2.19 1.63 2.42
1-1/2″ 38.100 0.448 0.666 0.556 0.828 0.773 1.15 1.01 1.51 1.28 1.9 1.65 2.45 1.8 2.68 1.99 2.96
1-3/4″ 44.450 0.523 0.779 0.652 0.97 0.907 1.35 1.19 1.77 1.51 2.24 1.94 2.89 2.12 3.16 2.35 3.5
2″ 50.800 0.599 0.892 0.746 1.110 1.040 1.54 1.36 2.03 1.73 2.57 2.24 3.33 2.45 3.65 2.71 4.04
2-1/2″ 63.500 1.3 1.94 1.72 2.56 2.18 3.24 2.83 4.21 3.1 4.61 3.44 5.12
3″ 76.200 1.57 2.34 2.7 3.08 2.63 3.91 3.42 5.09 3.75 5.58 4.17 6.2
3-1/2″ 88.900 1.83 2.73 2.43 3.61 3.08 4.58 4.01 5.97 4.4 6.55 4.9 7.29
4″ 101.600 2.1 3.13 2.78 4.13 3.53 5.25 4.6 6.85 5.05 7.52 5.62 8.37

 


STANDARD WIRE GAUGE (SWG)

 

Tube Outside Diameter

22 20 18 16 14 12 11 10

inch

.028

mm 0.711

inch

.036

mm 0.914 inch 0.48 mm 1.218 inch 0.64 mm 1.625 inch 0.80 mm 2.032 inch 0.104 mm 2.641 inch 0.116 mm 2.946 inch 0.128 mm 3.251
inch mm lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m lb/ft k/m
1/4″ 6.350 0.830 0.124 0.105 0.157 0.129 0.192
5/16″ 7.950 0.108 0.161 0.138 0.205 0.173 0.257
3/8″ 9.525 0.132 0.197 0.170 0.253 0.216 0.321 0.256 0.381
1/2″ 12.700 0.143 0.213 0.181 0.27 0.235 0.35 0.303 0.451 0.365 0.543 0.447 0.665 0.484 0.720
5/8″ 15.875 0.181 0.270 0.230 0.342 0.300 0.447 0.390 0.580 0.473 0.704 0.588 0.875 0.641 0.954
3/4′ 19.050 0.279 0.415 0.366 0.544 0.476 0.709 0.582 0.866 0.732 1.09 0.800 1.19 0.867 1.29
7/8″ 22.225 0.257 0.383 0.328 0.488 0.431 0.641 0.563 0.838 0.692 1.03 0.874 1.3 0.954 1.42 1.04 1.55
1″ 25.400 0.296 0.44 0.376 0.56 0.496 0.738 0.65 0.967 0.8 1.19 1.02 1.51 1.12 1.66 1.21 1.8
1-1/4″ 31.750 0.372 0.553 0.474 0.706 0.626 0.931 0.827 1.23 1.02 1.51 1.3 1.93 1.43 2.13 1.56 2.32
1-1/2″ 38.100 0.448 0.666 0.572 0.851 0.759 1.13 0.994 1.48 1.24 1.84 1.58 2.35 1.74 2.59 1.91 2.84
1-3/4″ 44.450 0.523 0.779 0.669 0.996 0.887 1.32 0.650 1.74 1.45 2.16 1.86 2.77 2.06 3.06 2.25 3.35
2″ 50.800 0.599 0.892 0.766 1.14 1.02 1.51 1.340 2.000 1.67 2.48 2.14 3.19 2.37 3.53 2.6 3.97
2-1/2″ 63.500 1.28 1.9 1.69 2.52 2.1 3.13 2.71 4.03 3.000 4.47 3.3 4.91
3″ 76.200 1.54 2.29 2.000 3.03 2.53 3.77 3.27 4.87 3.63 5.4 3.99 5.94
3-1/2″ 88.900 1.79 2.67 2.390 3.55 2.97 4.42 3.83 5.7 4.26 6.34 4.68 6.97
4″ 101.600 2.06 3.06 2.740 4.07 3.41 5.07 4.4 6.54 4.89 7.28 5.38 8.01


SWG TUBE SIZES CONVERSION (INCHES/MM)

SWG to inches and millimeters conversion

SWG inches  mm
7/0 0.5 12.7
6/0 0.464 11.786
5/0 0.432 10.973
4/0 0.4 10.16
3/0 0.372 9.449
2/0 0.348 8.839
1/0 0.324 8.236
1 0.3 7.62
2 0.276 7.01
3 0.252 6.401
4 0.232 5.893
5 0.212 5.385
6 0.192 4.877
7 0.176 4.47
8 0.16 4.064
9 0.144 3.658
10 0.128 3.251
11 0.116 2.946
12 0.104 2.642

SWG  inches  mm
13 0.092 2.337
14 0.08 2.032
15 0.072 1.829
16 0.064 1.626
17 0.056 1.422
18 0.048 1.219
19 0.04 1.016
20 0.036 0.914
21 0.032 0.813
22 0.028 0.711
23 0.024 0.61
24 0.022 0.559
25 0.02 0.508
26 0.018 0.457
27 0.0164 0.417
28 0.0148 0.376
29 0.0136 0.345
30 0.0124 0.315
31 0.0116 0.295

SWG  inches  mm
32 0.0108 0.274
33 0.01 0.254
34 0.0092 0.234
35 0.0084 0.213
36 0.0076 0.193
37 0.0068 0.173
38 0.006 0.152
39 0.0052 0.132
40 0.0048 0.122
41 0.0044 0.112
42 0.004 0.102
43 0.0036 0.091
44 0.0032 0.081
45 0.0028 0.071
46 0.0024 0.061
47 0.002 0.051
48 0.0016 0.041
49 0.0012 0.03
50 0.001 0.025

Download BWG vs SWG Chart

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Tube BWG vs. SWG.pdf