Speaker Wire Gauge Calculator + Helpful Wire Info

Looking for the best way to find the right speaker wire gauge? You’re in the right place!

My custom speaker wire gauge calculator will make finding the right wire size a snap.

UPDATE! I’ve upgraded the calculator for a wider range of common wire sizes and higher power.

Note: Javascript must be enabled in your browser to see or use the tool.


speaker wire gauge calculator image

This custom-designed speaker wire gauge calculator will calculate the electrical current carried based on your specific inputs:

  • Amplifier or stereo power per speaker channel
  • Speaker Ohms
  • Any length of wire you need in feet or meters

Using this, it will find the smallest speaker wire gauge that will work for your specific needs. My goal in designing this wire size calculator was to help you spend less money, avoid buying more wire than is needed, and keep wire use/installation hassle to a minimum.

Sometimes you can save money by buying shorter lengths of wire or using a smaller gauge than you thought you could otherwise. Feel free to play around with different lengths, exact speaker Ohm values, and power ratings to see what will work best for your speaker system.


  1. Input your values:
    • Wire length in Feet or Meters: This can be whole numbers or fractions (5 ft, 2.6 ft, etc.).
    • RMS/continuous power for your amp or stereo: Up to 3,000W RMS  (Do not use “peak” or “max.” power ratings – this will throw your results WAY off.) 
    • The speaker impedance in Ohms (Ω): 0.5 to 100 Ohms.
  2. Touch the button to display your wire size data.

The wire calculator will output:

  • The smallest acceptable wire size with 5% or less power loss for both copper and copper-clad aluminum (CCA) wire.
  • The total power loss across the wire, in Watts, at maximum power output.
  • You will see “N/A” if the calculator cannot provide a large enough wire based on what you’ve entered. This should only happen in cases with very high power, low speaker Ohms, and/or very long wire lengths.
  • “4/0” wire size a size larger than 2AWG is needed.

Note that if a wire gauge is recommended but you cannot find that size available, step up to the next largest size. (Example: The next size above 6AWG to use would be 4AWG).

How the calculator is different from a wire size chart

  • Wire size charts are typically based on only a few factors like length or speaker Ohms and aren’t tailored to your specific needs.
  • A speaker wire gauge chart is helpful if you only have very basic specs or need something simple to use as a guideline.

The benefit of my calculator is that it can take into account nearly any speaker wire length and uses the power (Watts) as a calculation factor. My goal is to help you figure out the best size speaker wire based on all the specs that matter and also help you find the smallest (least expensive) wire size that is best for you.

Money-saving speaker wire tips

As genuine copper wire is more expensive these days and since most people don’t drive speakers at full power, here are some ways to make the best of that and save money on wire:

  • If you (like most people) rarely use your amp or stereo output above 50%-60% power, you can go down one wire AWG gauge. That’s because you’ll never reach the wire’s current capacity if you don’t use maximum power – there’s no need for a larger wire most of the time in that case.
  • Have surplus wire lying around unused? You can double-up or even triple-up smaller gauge wire to get the same gauge as a thicker wire size. For example, using two lengths of 18AWG in parallel will be roughly the same as a 16AWG wire.
  • For most surround sound or center channel home theater speakers, you don’t need a large gauge or costly speaker cables. Their power needs are usually low and don’t require as much power.

Is oxygen free speaker wire worth it?

No, oxygen-free pure copper wire will not deliver a noticeable improvement in sound or power handling. It’s simply not worth the extra money.

It’s a great marketing feature for retailers but the data shows an amazingly small difference in performance. Paying more is a waste of money. As long as you’re using a good quality wire with the correct gauge, you’ll be fine.

In fact, you’d need very sophisticated lab equipment to even measure any difference at all!

Heads up! Copper vs copper clad aluminum (CCA) speaker wire differences

Copper clad aluminum vs copper speaker wire illustrated diagram

Because of what I’ve seen in stores and how they’re different, it’s important to talk about copper vs copper-clad aluminum (CCA) wire. Over the last few years, the price of copper has increased, resulting in manufacturers and retailers substituting real copper speaker wire with non-pure copper wire without telling you!

This means if you’re not aware you could be using wire that’s not sufficient – or even get ripped off!

TIP: If a roll or package of speaker wire does not say “copper” or “100% copper” etc. on the packaging, it’s most likely CCA wire. Sadly, these days it’s becoming more common to be misled by manufacturers as far as the type of wire you’re buying is concerned.

Why CCA wire falls short compared to copper

Unlike pure copper wire, copper-clad aluminum is based on an aluminum wire core with a thin copper plating. Sure – from the outside, you’ll see the copper finish and it looks the same…but is it really?

The problem is that aluminum wire has only 61% of the conductivity of copper wire (it has 39% higher resistance to the flow of electrical current). You won’t get the same performance at the same wire gauge.

This means a larger CCA wire gauge is needed to get the same power handling, amp capacity, and resistance you’d get with real copper wiring.

Does it matter for everyday use?

For everyday, average listening and low or moderate power levels, it’s not a problem and you’ll be fine. However, if you’re going to drive speakers with high power levels, in a high-quality stereo system or speaker system, or want the wire capacity you should get, you’ll probably want to look for 100% copper wire.

Alternatively, you can use CCA wire and still get the same performance by “sizing up.” To do so, you’ll need to move up at least one speaker wire gauge when buying CCA speaker wire. 

For example, to replace 18 gauge copper wire, use a 16AWG or 14AWG CCA wire.

TIP: CCA somewhat less flexible than copper stranded speaker wire. For speaker wire runs or car audio installations where flexibility is important, be aware of this difference.

About the author

Marty is an experienced electrical, electronics, and embedded firmware design engineer passionate about audio and DIY. He worked professionally as an MECP-certified mobile installer for years before moving into the engineering field. Read more »

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