As a general rule, the smaller the diameter of the wire, the higher the resistance and thus lower current capability over a given length. It is almost always acceptable to use a larger gauge wire. When in doubt about the load, go up a gauge. Other factors can affect the capacity of wires besides the length, such as a hot environment, duration of load, stranded vs. solid wire, wire plating, etc. Approximate metric wire size equivalents (with some rounding) are included in the table as diameter/area and are in millimeters/square millimeters [mm/mm2].

To use the calculator, select the operating voltage, type in the maximum current in Amps of the circuit, and then enter the length of the wire. To see the results, press the “Calculate” button. If the wire gauge is okay to use, it will generate a check mark. The 'Max Length’ column indicates the maximum length of wire of that gauge that can be used at the given values entered.

Voltage drop 2% is suitable for most applications. 1% is better and 5% might cause flickering or poor performance in dimming systems.

This table is a general guide for MOST applications. By utilizing this Wire Calculator, you are doing so at YOUR OWN RISK. This calculator is a helpful guide, not an absolute authority. It is recommended to utilize a professional electrician or an engineering company to perform the calculations in your application.