AWG Wire Sizes (see table below)

AWG: In the American Wire Gauge (AWG), diameters can be calculated by applying the formula D(AWG)=.005·92((36-AWG)/39) inch. For the 00, 000, 0000 etc. gauges you use -1, -2, -3, which makes more sense mathematically than "double nought." This means that in American wire gage every 6 gauge decrease gives a doubling of the wire diameter, and every 3 gauge decrease doubles the wire cross sectional area. Similar to dB in signal and power levels. An approximate form of this formula contributed by Mario Rodriguez is D = .460 * (57/64)(awg +3) or D = .460 * (0.890625)(awg +3).


Metric Wire Gauges (see table below)
Metric Gauge: In the Metric Gauge scale, the gauge is 10 times the diameter in millimeters, so a 50 gauge metric wire would be 5 mm in diameter. Note that in AWG the diameter goes up as the gauge goes down, but for metric gauges it is the opposite. Probably because of this confusion, most of the time metric sized wire is specified in millimeters rather than metric gauges.

Load Carrying Capacities (see table below)
The following chart is a guideline of ampacity or copper wire current carrying capacity following the Handbook of Electronic Tables and Formulas for American Wire Gauge. As you might guess, the rated ampacities are just a rule of thumb. In careful engineering the voltage drop, insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account. The Maximum Amps for Power Transmission uses the 700 circular mils per amp rule, which is very very conservative. The Maximum Amps for Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle. For short lengths of wire, such as is used in battery packs you should trade off the resistance and load with size, weight, and flexibility. NOTE: For installations that need to conform to the National Electrical Code, you must use their guidelines. Contact your local electrician to find out what is legal!

AWG gauge

Conductor
Diameter Inches

Conductor
Diameter mm

Ohms per 1000 ft.

Ohms per km

Maximum amps for chassis wiring

Maximum amps for
power transmission

Maximum frequency for
100% skin depth for solid conductor copper

OOOO

0.46

11.684

0.049

0.16072

380

302

125 Hz

OOO

0.4096

10.40384

0.0618

0.202704

328

239

160 Hz

OO

0.3648

9.26592

0.0779

0.255512

283

190

200 Hz

0

0.3249

8.25246

0.0983

0.322424

245

150

250 Hz

1

0.2893

7.34822

0.1239

0.406392

211

119

325 Hz

2

0.2576

6.54304

0.1563

0.512664

181

94

410 Hz

3

0.2294

5.82676

0.197

0.64616

158

75

500 Hz

4

0.2043

5.18922

0.2485

0.81508

135

60

650 Hz

5

0.1819

4.62026

0.3133

1.027624

118

47

810 Hz

6

0.162

4.1148

0.3951

1.295928

101

37

1100 Hz

7

0.1443

3.66522

0.4982

1.634096

89

30

1300 Hz

8

0.1285

3.2639

0.6282

2.060496

73

24

1650 Hz

9

0.1144

2.90576

0.7921

2.598088

64

19

2050 Hz

10

0.1019

2.58826

0.9989

3.276392

55

15

2600 Hz

11

0.0907

2.30378

1.26

4.1328

47

12

3200 Hz

12

0.0808

2.05232

1.588

5.20864

41

9.3

4150 Hz

13

0.072

1.8288

2.003

6.56984

35

7.4

5300 Hz

14

0.0641

1.62814

2.525

8.282

32

5.9

6700 Hz

15

0.0571

1.45034

3.184

10.44352

28

4.7

8250 Hz

16

0.0508

1.29032

4.016

13.17248

22

3.7

11 k Hz

17

0.0453

1.15062

5.064

16.60992

19

2.9

13 k Hz

18

0.0403

1.02362

6.385

20.9428

16

2.3

17 kHz

19

0.0359

0.91186

8.051

26.40728

14

1.8

21 kHz

20

0.032

0.8128

10.15

33.292

11

1.5

27 kHz

21

0.0285

0.7239

12.8

41.984

9

1.2

33 kHz

22

0.0254

0.64516

16.14

52.9392

7

0.92

42 kHz

23

0.0226

0.57404

20.36

66.7808

4.7

0.729

53 kHz

24

0.0201

0.51054

25.67

84.1976

3.5

0.577

68 kHz

25

0.0179

0.45466

32.37

106.1736

2.7

0.457

85 kHz

26

0.0159

0.40386

40.81

133.8568

2.2

0.361

107 kH

27

0.0142

0.36068

51.47

168.8216

1.7

0.288

130 kHz

28

0.0126

0.32004

64.9

212.872

1.4

0.226

170 kHz

29

0.0113

0.28702

81.83

268.4024

1.2

0.182

210 kHz

30

0.01

0.254

103.2

338.496

0.86

0.142

270 kHz

31

0.0089

0.22606

130.1

426.728

0.7

0.113

340 kHz

32

0.008

0.2032

164.1

538.248

0.53

0.091

430 kHz

Metric 2.0

0.00787

0.200

169.39

555.61

0.51

0.088

440 kHz

33

0.0071

0.18034

206.9

678.632

0.43

0.072

540 kHz

Metric 1.8

0.00709

0.180

207.5

680.55

0.43

0.072

540 kHz

34

0.0063

0.16002

260.9

855.752

0.33

0.056

690 kHz

Metric 1.6

0.0063

0.16002

260.9

855.752

0.33

0.056

690 kHz

35

0.0056

0.14224

329

1079.12

0.27

0.044

870 kHz

Metric 1.4

.00551

.140

339

1114

0.26

0.043

900 kHz

36

0.005

0.127

414.8

1360

0.21

0.035

1100 kHz

Metric 1.25

.00492

0.125

428.2

1404

0.20

0.034

1150 kHz

37

0.0045

0.1143

523.1

1715

0.17

0.0289

1350 kHz

Metric 1.12

.00441

0.112

533.8

1750

0.163

0.0277

1400 kHz

38

0.004

0.1016

659.6

2163

0.13

0.0228

1750 kHz

Metric 1

.00394

0.1000

670.2

2198

0.126

0.0225

1750 kHz

39

0.0035

0.0889

831.8

2728

0.11

0.0175

2250 kHz

40

0.0031

0.07874

1049

3440

0.09

0.0137

2900 kHz

 

 

 

 

 

 

 

 

 

Voltage Drop Calculator by Gerald Newton http://www.electrician2.com


The following calculator calculates the voltage drop, and voltage at the end of the wire for American Wire Gauge from 4/0 AWG to 30 AWG, aluminum or copper wire. (Note: It just calculates the voltage drop, consult the above table for rules-of-thumb, or your local or national electrical code or your electrician to decide what is legal!) Note that the voltage drop does not depend on the input voltage, just on the resistance of the wire and the load in amps.

Select Copper or Aluminum

Select American Wire Gauge (AWG) Size

Select Voltage

Enter 1-way circuit
length in feet (the calculation is for the round trip distance)

Enter Load
in amps

 

Voltage drop

Voltage at load end of circuit

Per Cent voltage drop

Wire cross section in circular mils