Wire Gauge Calculator

During transformer/ciol design we have to decide how much thick wire will be able to carry required amount of charge through it. Wires are divided according to their thickness/area of cross section. Each wire is assigned a number according to Standard Wire Gauge (SWG). This number is called SWG number of that wire. We know, a thick wire will be able to carry more charge than a thin wire. Here, I have considered circular mils (cmils) as unit of cross sectional area measurement.

Now, there is no need to look up a table/chart against your required value of current for wire selection. This smart and free app will do this work for you.

How It Works?

It takes two values as input. First is Current that has to be passed through wire, so wire should be able to carry this value of current. Second value is Rate circular mils per ampere.
It generates two output values as well. First is SWG number of a wire that is safe for given value of current and it’s actual rate. Second value is the SWG number of next wire that may be or may be not near the required wire with it’s actual rate. You can decide yourself which SWG wire will be better for your current requirement.

First enter value of Current.

Now, enter value of Rate. In open air wires remain cool and can pass charge at more rate means with less cross sectional area a wire can pass more charge and so more current. But, when we use same wire in transformer/coil winding where wires are wound in layers, one layer over other and there is no air present between these layers but there is paper between them, so wires fail to get cool due to air, their charge passing capability is reduced and so, can pass charge at lower rates. Usually, we double rate (area) in transformers than in open air. We use 500 cmils/Amp value or more for transformers. There are so many other factors that affect this value, some of which are temperature, peak load time, working duration of machine per day etc. So, you have to choose better value of Rate considering all these factors.

Now, you press “CALCULATE” button and results will be shown to you as in the following figure.