How to Convert Metric Cable Size to AWG

Cables are usually sized directly using the metric diameter or the American wire gauge (AWG). An increasing wire size decreases the gauge of the wire. The AWG scale spans from 11.684 mm to 0.0779 mm (No. 0000 AWG to No. 40 AWG) with 39 step sizes in between. Cable size is an important parameter which directly correlates to the cross sectional area of the wire, which affects the electrical (conductance and resistance) and mechanical properties of the wire.

Wire is sized using metric diamter or the American wire gauge.
  1. Convert the metric wire diameter into millimeters. For example, if the wire diameter is given as 0.005827 meters, multiple by a factor of 1,000 to obtain 5.827 millimeters.

  2. Input the wire diameter (in millimeters) into the equation AWG = (-ln(d)+2.1104)/(0.11594), where d is the wire diameter in millimeters and AWG is the American wire gauge number. A wire diameter of 6.544 millimeters equates to a No. 2 AWG wire.

  3. Reconvert wire given in AWG to a metric wire size using the equation d = exp^(2.1104-0.11594*AWG). Using this equation, a No. 1 AWG wire has a diameter of 6.544 millimeters.


  • The above conversions do not apply to steel wiring. An alternative scale is used to size wires of this material.

About the Author

Michael Peter has been a technical writer since 2006 for a power/start-up company and has published scientific papers in research journals including "Analytical Chemistry" and "Electrochimica Acta." He holds a Bachelor of Science in mechanical engineering and is currently completing his Ph.D. related to nano/microfludics and spectroscopy.