Wire Diameter/Area Calculations

This calculator can be use to convert to/from American Wire Gauge (AWG)/Standard Wire Gauge (SWG) wire sizes, and diameters, in mm and inches. For the gauge or diameter entered, it also provides the wire resistance and equivalent gauges for wires in parallel.

Note: The parallel wire section is only meant for internal chassis wiring where you might want to parallel two or more wires to reduce the overall voltage drop. It is not intended for home or industrial wiring. For information on the requirements associated with parallel wires in home or industrial wiring, please refer to the National Electrical Code, Section 310.4.

Enter Wire Size Select AWG, SWG, in, or mm

AWG SWG
in mm
Bare Enameled
Gauge Diameter
AWG # SWG # Inches mm
14 16 0.064 1.628
Area
4.107 kcmil* 2.081 mm2
* kcmil = Thousands of Circular Mils
Resistance
2.525 Ohms/1000 ft 8.282 Ohms/km
For Wires in a Bundle
Equivalent Areas
AWG # SWG # kcmil mm2
9 12 12.32 6.243


When AWG is selected, these equations are used to convert to inches and mm. Where, "n" is the AWG wire gauge entered. Because there isn't a nice neat equation for SWG wire sizes, the nearest SWG gauge is looked up in a SWG/mm table.


When SWG is selected, the size in mm is first looked up in a SWG/mm table and then the nearest AWG gauge is calculated using these equations. Where, "d" is the wire diameter in mm. Also listed is the equation to calculate AWG if you had the diameter in inches.

Note: The AWG gauge listed is rounded up or down, depending on the output of the calculation. So, the AWG gauge listed can be as much as 1/2 gauge off, plus or minus. If you are trying to select a wire for it's current capacity, choose the next lowest AWG gauge to be safe.


Cross sectional areas are calculated using these equations. Again, "n" is the AWG wire gauge entered. SWG, mm, or inch inputs are first converted to AWG and then the area is calculated. Area is listed in kcmil (Thousands of Circular Mills) and mm2 (Milimeters Square).

For the 1/0, 2/0, 3/0, 4/0 wire gauges, enter either 0, 00, 000, 0000 or 0, -1, -2, -3, respectively. AWG sizes bigger than 4/0 or smaller than 40, are not usable with this calculator.

Selecting Enameled wire, subtracts 0.005 inches (0.127 mm) from your diameter entry. However, the thickness of the enamel depends on the wire size and class of enamel. Wires with smaller diameters usually get thinner enamel coatings than larger diameter wires. Plus many manufactures rate the thickness by "Class". Higher "Class" coating numbers are generally thicker. If you are trying to determine the gauge of a enameled wire, it might be best to remove the enamel from a small section before measuring. When entering an AWG number, the Bare/Enameled selector is ignored.

Some Rules of Thumb

  • When the diameter of a wire is doubled, the AWG will decrease by 6. for example, a #2 AWG wire is about twice the diameter of #8 AWG wire.
  • When the cross-sectional area of a wire is doubled, the AWG will decrease by 3. For example, two #14 AWG wires have about the same cross-sectional area (kcmil or mm2) as a single #11 AWG wire.
  • A decrease of ten gauge numbers, for example from No. 10 to 1/0, multiplies the area and weight by approximately 10 and reduces the resistance by a factor of approximately 10.