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What Gauge Wire for 1200 Watt Amp? 2 or 4 Gauge?

Written by Edwin Jones / Fact checked by Andrew Wright

what gauge wire for 1200 watt amp

Different car amplifier ratings require different voltages with specific wire sizes to achieve the finest sound quality possible. If you’re wondering what gauge wire for 1200 watt amp, the answer is simple.

For this amplifier rating, 2 gauge is the typical choice. However, since there are factors that might affect the wire’s rating, there is a more detailed trick to determining the best-recommended size. In this case, let us go through all of the details below.

What Gauge Wire for Amp with a Rating of 1200 Watts?

Even though most electricians recommend a 2 gauge wire for a 1000 to 1500 watt amp, it is not a good idea to always stick with this size. Not all sound units are the same, and many factors might affect the supply voltage, making the cable insufficient for the unit’s load.

In order to get the proper wire gauge for amplifier, you should first consider these factors and the proper calculation below.

Factors to Consider in Getting the Proper Gauge Power Wire for Amp


1. Class of Amps

The first thing you should know is how efficient your amplifier is. This is because no amp unit is 100% efficient. Typically, you can come across two most common classes of amplifiers in the market today. These are Class D, which is 80% efficient, and Class AB, which is 50% efficient.

To identify your amp’s class or efficiency, you can look at its user manual.

2. Type of Wire

Always remember that there is a specific cable for every application. Therefore, for this scenario, it is only recommended to use a wire designed for car audio. On the whole, you’ll find Copper-Clad Aluminum (CCA) and Oxygen-Free Copper (OFC) wires.

A CCA wire is cheap but has higher resistance compared to its OFC counterpart. In this case, if you choose to use CCA, you might need a larger gauge than you would for an OFC wire.

3. Wire Length

Another thing you should consider is the wire length of the application. It is because any setup requiring a longer wire will result in a high voltage drop as resistance increases. This may result in an insufficient power supply that may cause trouble to the unit.

In this case, measuring the total cable length from the battery’s positive side up to the amp unit and its ground connection is best.

How to Calculate the Proper Wire Gauge for the Amp?

wire gauge amp chart

To get the recommended wire gauge for the amp, you need to first get the unit’s power total using the formula: Power = total RMS watts divided by the unit efficiency percentage.

Power (watts) = \frac{Total RMS Watts}{\frac{Efficiency Percentage}{100}}

Then, get the total current draw through Ohm’s law:

Current = \frac{Power}{System~Voltage}

For example, we have a 1200 watts class D amp. In this case, 1200 divided by 80% is 1500 power total. Then, divide this power total by the unit’s voltage rating of 13.8 volts, and we get 108.6 amps. This means that this unit draws 108.6 amps, and we need a wire that can hold this current amount.

In this case, you should refer to a car amp wire gauge chart that you can find online. You will see there the corresponding wire gauge for every unit total current with the length you need.

In this case, 108.6 amps demand 8 gauge at 7 feet or less, 4 gauge at 19 feet, and 2 gauge at 22 feet.

Also, note that there is no problem with using a larger wire than the recommendation. Therefore, for 1200 watts amps, the ideal wire size is a 2 gauge OFC wire.

Can 4 Gauge Wire Handle 1200 Watts?


Using the calculation above and based on the wire gauge amp chart, a 4 gauge wire can handle 1200 watts for class D amps. However, it is only applicable if the application length is 19 feet maximum.

A 4 gauge wire will be perfect for a unit with less current than a 1000 watt amp in a 22 ft. application. If you need more than this length or have a class AB amp that is 50% efficient, you might consider a larger wire up to 1/0 gauge to prevent voltage loss.

Frequently Asked Questions

What Gauge Wire is Best for an Amplifier?

As mentioned earlier, the amperage will determine the proper wire gauge for an amp. Using the above calculation, I’ve made a list of recommended wire gauges for each amp rating.

For a smaller amplifier:

  • For a 300 watt amp, use 8 gauge wires for a class D unit and 6 or 4 gauge wires for a class AB unit.
  • For a 600 watt amp, you may need 4 or 6 gauge wires for class D and only 4 gauge for class AB.

For a higher amplifier rating:

Which is Better Between 4 Gauge Vs 8 Gauge?

If the 8 gauge wire is already a perfect match for your amp, upgrading it to a greater size will be a waste of money. However, if you intend to modify your device in the future, it makes sense to use a much larger wire than the recommended one.

Which to use – 0 Gauge Wire Vs 4 Gauge?

Using the larger wire size is preferable if you have a multi-amp system. In this instance, it is strongly advised that you choose the 0 gauge so that if you decide to update or add an amp unit in the future, your wire will be ready.


Knowing what gauge wire for 1200 watt amp or any amp rating is essential, since it might alter the quality of your audio. This task is quite straightforward, and you may use the above guide to calculate the proper wire gauge.

However, you must take precautions when searching for high-quality cables. It is best to check the insulation label and do some research on the manufacturer to ensure the wire quality.

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