Practical Electronics/SWG

The thickness of a wire is often given as a Standard Wire Gauge, or SWG. This is number from 0000000 or 7/0 (thickest) to 50 (thinnest). The gauge of most wire used in electronics is between 20 and 30. Often, a wire gauge will be stated followed by "swg", so 26 swg, etc.

It is very important that you do not confuse SWG with AWG, which means American Wire Gauge - although fairly similar, it is a different system of sizing wires.

The table below lists the SWG gauges, along with the diameter in inches and millimetres.

= '''WARNNIG!!! This table appears to be incorrect'''. From measurement and also from another website (that I am unable to link due to policies) a copper wire of about 0.127mm diameter has a resistance of 1426 Ohms/km, whereas this table above states that a thicker wire of 0.132mm diameter has a resistance of 4130 Ohms/km, much higher. I suggest that anyone using this table for important work should check elsewhere. WARNING!!! WRONG!!! = This table appears to be incorrect. From measurement and also from another website (that I am unable to link due to policies) a copper wire of about 0.127mm diameter has a resistance of 1426 Ohms/km, whereas this table above states that a thicker wire of 0.132mm diameter has a resistance of 4130 Ohms/km, much higher. I suggest that anyone using this table for important work should check elsewhere.