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Standard Wire Gauge “SWG” Calculator – SWG Size Chart & Table

SWG “Standard Wire Gauge” Size Calculator & Cable Properties Table & Chart

Standard Wire Gauge “SWG” Calculator

The following Standard Wire Gauge (SWG) calculator will calculate the diameter in inches, mm, cross sectional area in inches2, mm2, and kcmil or MCM, resistance per 1000 feet and per 1000 meters and the maximum current capacity in amperes. To calculate the values, just select or enter the SWG size and hit the “Calculate” button to get the result of different properties of SWG cables and wires.

Select Gauge #:
Selected Gauge #: SWG
Select Wire Type:
Resistivity “ρ” : Ω.m
  
Diameter in Inches: in
Diameter in Millimeters: mm
Cross Sectional Area in Square Inches: in2
Cross Sectional Area in Square Millimeters: mm2
Cross Sectional Area in kilo Circular Mils: kcmil
Resistance per 1000 Feet*: Ω/kft
Resistance per 1000 Meters*: Ω/km

Good to know: SWG or Standard Wire Gauge used for wire sizing and properties is also known as “British Standard Wire Gauge” and “British Standard Gauge” or “Imperial Wire Gauge”.

*The data for resistance of copper and other wires in Ω/km and Ω/kft are at 20°C or 68°F.

Related Calculators:

Wire Diameter in mm & Inch, Area in inch2, mm2 & kcmil and Resistance in Ω/kft & Ω/km Calculations

Wire Diameter in Inches “in”.

dn = 5 x 10-3 x 92(36-n)÷39 = 0.005 x 92(36-n)÷39

Wire Diameter in mm “millimeters”.

dn = 27 x 10-3 x 92(36-n)÷39 = 0.27 x 92(36-n)÷39

Wire Cross Sectional Area in Square Inches “in2“.

An (π ÷ 4) dn2= 19635 x 10-6 x 92(36-n)÷19.5

Wire Cross Sectional Area in Square Millimeter “mm2“.

An = (π ÷ 4) x dn2 = 12.668 x 10-3 x 92(36-n)÷19.5

Wire Cross Sectional Area in kcmil “kilo circular mils”.

An = 1000 dn2 = 0.025 x 92(36-n)÷19.5

Wire Resistance per 1000 feet at 20°C or 68°F:

R= 0.3048 x 109 × ρ ÷ (25.42An)

Wire Resistance per 1000 Meters at 20°C or 68°F:

R= 109 x ρ ÷ An

Where: 

  • n = Number of the gauge size. 
  • d = The wire diameter in inches, mm, inches2, & mm2 respectively.
  • An = Cross sectional area of “n” gauge wire size in inches2, “mm2” & kcmil respectively.
  • R = Resistance of the wire conductors in Ω/kft & Ω/km respectively.
  • ρ = rho = resistivity in (Ω·m).

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Standard Wire Gauge “SWG” Size Chart & Table

The following SWG “Standard Wire Gauge” table shows the SWG size and diameter in inches “in” and millimeter “mm”, its cross section area in Inches2, mm2, and kcmil or MCM and resistance in ohms per 1000 feet and 1000 meter. The SWG size chart also shows the maximum capacity of current in amperes.

SWG Diameter Cross Section Area Resistance in Ω Max Current “A”
inch mm inch2 mm2 kcmil Ω / kft Ω / km Amp Capacity
7/0 0.500 12.700 0.1963 126.6769 250 0.0414 0.136 305.5
6/0 0.464 11.786 0.1691 109.0921 215 0.0481 0.158 264.8
5/0 0.432 10.973 0.1466 94.5638 187 0.0554 0.182 227.0
4/0 0.400 10.160 0.1257 81.0732 160 0.0647 0.213 196.3
3/0 0.372 9.449 0.1087 70.1202 138 0.0748 0.246 171.8
2/0 0.348 8.839 0.0951 61.3643 121 0.0854 0.281 148.9
0 0.324 8.230 0.0824 53.1921 105 0.0986 0.324 127.7
1 0.300 7.620 0.0707 45.6037 90.0 0.1150 0.378 108.1
2 0.276 7.010 0.0598 38.5989 76.2 0.1358 0.447 90.1
3 0.252 6.401 0.0499 32.1780 63.5 0.1629 0.536 76.4
4 0.232 5.893 0.0423 27.2730 53.8 0.1922 0.632 63.8
5 0.212 5.385 0.0353 22.7735 44.9 0.2302 0.757 52.3
6 0.192 4.877 0.0290 18.6793 36.9 0.2807 0.923 44.2
7 0.176 4.470 0.0243 15.6958 31.0 0.3340 1.10 33.3
8 0.160 4.064 0.0201 12.9717 25.6 0.4042 1.33 26.5
9 0.144 3.658 0.0163 10.5071 20.7 0.4990 1.64 21.2
10 0.128 3.251 0.0129 8.3019 16.4 0.6315 2.08 16.6
11 0.116 2.946 0.0106 6.8183 13.5 0.7689 2.53 13.6
12 0.104 2.642 0.0085 5.4805 10.8 0.9566 3.15 10.9
13 0.092 2.337 0.0066 4.2888 8.46 1.2224 4.02 8.58
14 0.080 2.032 0.0050 3.2429 6.40 1.6166 5.32 6.49
16 0.072 1.626 0.0041 2.0755 5.18 1.9958 6.56 5.25
15 0.064 1.829 0.0032 2.6268 4.10 2.5260 8.31 4.15
17 0.056 1.422 0.0025 1.5890 3.14 3.2992 10.9 3.18
18 0.048 1.219 0.0018 1.1675 2.30 4.4906 14.8 2.33
19 0.040 1.016 0.0013 0.8107 1.60 6.4665 21.3 1.62
20 0.036 0.914 0.0010 0.6567 1.30 7.9833 26.3 1.31
21 0.032 0.813 0.0008 0.5189 1.02 10.104 33.2 1.038
22 0.028 0.711 0.0006 0.3973 0.784 13.197 43.4 0.794
23 0.024 0.610 0.0005 0.2919 0.576 17.962 59.1 0.584
24 0.022 0.559 0.0004 0.2452 0.484 21.377 70.3 0.490
25 0.020 0.5080 0.0003 0.2027 0.400 25.866 85.1 0.405
26 0.018 0.4572 0.00025 0.1642 0.324 31.933 105 0.328
27 0.0164 0.4166 0.00021 0.1363 0.269 38.468 127 0.273
28 0.0148 0.3759 0.00017 0.1110 0.219 47.235 155 0.222
29 0.0136 0.3454 0.00014 0.0937 0.185 55.938 184 0.187
30 0.0124 0.3150 0.00012 0.0779 0.154 67.289 221 0.159
31 0.0116 0.2946 0.00010 0.0682 0.135 76.890 253 0.136
32 0.0108 0.2743 0.00009 0.0591 0.117 88.703 292 0.118
33 0.0100 0.2540 0.00008 0.0507 0.100 103.46 340 0.101
34 0.0092 0.2337 0.00007 0.0429 0.0846 122.24 402 0.086
35 0.0084 0.2134 0.00005 0.0358 0.0706 146.63 482 0.071
36 0.0076 0.1930 0.00004 0.0293 0.0578 179.13 589 0.0586
37 0.0068 0.1727 0.00003 0.0234 0.0462 223.75 736 0.0469
38 0.0060 0.1524 0.000028 0.0182 0.0360 287.39 945 0.036
39 0.0052 0.1321 0.000021 0.0137 0.0270 382.63 1260 0.027
40 0.0048 0.1219 0.00001809 0.0117 0.0230 449.06 1480 0.023
41 0.0044 0.1118 0.00001522 0.0098 0.0194 534.46 1760 0.019
42 0.004 0.1016 0.00001257 0.0081 0.0160 646.64 2130 0.016
43 0.0036 0.0914 0.00001017 0.0066 0.0130 798.33 2630 0.013
44 0.0032 0.0813 0.00000805 0.0052 0.0102 1010.38 3320 0.010
45 0.0028 0.0711 0.00000615 0.0040 0.00784 1319.68 4340 0.008
46 0.0024 0.0610 0.00000453 0.0029 0.00576 1796.24 5910 0.006
47 0.0020 0.0508 0.00000314 0.0020 0.00400 2586.58 8510 0.004
48 0.0016 0.0406 0.00000201 0.0013 0.00256 4041.53 13300 0.003
49 0.0012 0.0305 0.00000113 0.0007 0.00144 7184.95 23600 0.0015
50 0.0010 0.0254 0.00000078 0.0005 0.00100 10346.3 34000 0.001

Notes:

  • The data for resistance of wires in Ω/km and Ω/kft are at 20°C or 68°F.
  • The current capacity for copper wire are at 200A/cm²

Here is the SWG wire size chart in image format if you need to download it for later use.

Standard Wire Gauge Table - SWG Size Chart

Related Electrical and Electronic Engineering Calculators:

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