Wire Gauge Current Calculator For Determining Cable Length for 12V Systems

You can use the calculator above to get a go/no-go whether or not the wire, at the needed length and wire gauge, can support the indicated current. The calculation is the following:

Length * 2 * Resistance Per Foot * Intended Max Current = Voltage Drop

A voltage drop above 1V (8.3% of 12V), you should increase the wire gauge as the current AWG at the specified length is insufficient. Anything lower than that is ok to use. When in doubt go a wire gauge higher. It doesn’t hurt to be beefier.

Note: Length is x2 for round trip. This is especially important if multi-conductor cable is used both for the supply path and the return path.

Don’t forget your fuses!

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