Wondering what size speaker wire you need? You’re in the right place!
In this guide, I’ll show you the proper gauge and type of speaker wire you need. I’ll also cover a lot more, too:
- Simple & quick rules of thumb for speaker wire size if that’s all you need to know.
- Speaker wire gauge and the American Wire Gauge chart explained.
- Understanding copper clad aluminum (CCA) vs pure copper wire so you don’t get ripped off.
- Solid vs stranded wire .
Contents
General tips: What size speaker wire do I need?
- For most low power home or car speakers (not subwoofers) 18 gauge (18AWG) is fine. 18AWG wire is good for about 50 watts for 4 ohms and 100 watts for 8 ohm loudspeakers up to 50 feet (15 m) or 100 feet (30 m) respectively.
- For higher power systems or longer lengths, 16 gauge is a great choice.
- For longer lengths (50-100ft)/(15-30.5m) you’ll need to go up 2 gauges (14 ga.) to avoid losing power. Very long lengths of speaker wire lose a bit of power over the long distance due to resistance. Using larger wire can help reduce or avoid this. (Use my speaker wire calculator to make it easy)
- A higher speaker impedance value (ex.: 6 or 8 ohm speakers) draws less current (lower amps) than lower impedance speakers. Therefore you often can use a thinner wire for them as you’ll see.
Simple “everyday” wire size table
| Wire Size | Recommended For |
|---|---|
| 18 AWG | Car and home speakers up to 25 ft with average power levels (50W RMS and below). |
| 16 AWG | Longer speaker runs for car & home stereo speakers or short runs under 20 ft for 75-100W. Moderate power subwoofers (under 225W) with short lengths. |
| 14 AWG | Long (100ft+) speaker runs or higher power applications such as high-power 2 or 4 ohm subwoofers with a short length. |
In most cases for everyday listening at medium or low power levels (50W RMS or under), 18 gauge (18AWG) wire is what you need.
It’s a good compromise between price and power handling as it’s usually affordable and easy to find.
How to find the correct size wire for ANY length or speaker system
The correct gauge speaker wire you need is based on 3 things:
- Your stereo or amplifier’s power output.
- The speaker’s impedance (Ohms) rating – also called the nominal impedance.
- The cable length needed for your speaker system.
However, I’ve made it easy for you: You can use my speaker wire size calculator or speaker wire size chart sections provided below.
SPEAKER WIRE GAUGE CALCULATOR
My speaker wire gauge calculator will recommend the right speaker wire gauge based on the power, speaker Ohms, and the specific length you need. This is different from the speaker wire size chart section below that provides lengths based on the speaker Ohms only and doesn’t need power ratings.
You can play around with different power amounts, lengths, and speaker Ohms to find the best speaker wire gauge for your audio setup and avoid spending more money than necessary.
HOW TO USE THE CALCULATOR:
- Enter the following:
- The wire length you need. This can be whole or fractions (5 ft, 2.6 ft, etc.).
- RMS/continuous power for your amp or stereo. (Do not use “peak” or “max.” power ratings.)
- The speaker impedance in Ohms (Ω).
- Touch the button to get the results.
The wire calculator will output:
- The smallest wire size with 5% or less power loss for both copper and copper-clad aluminum (CCA) wire.
- The power loss across the wire, in Watts, at maximum power output.
SPEAKER WIRE GAUGE CHART
The chart and tables above are handy if you aren’t sure about your stereo or amplifier power. You can estimate the length of wire you can use without losing a lot of power (at maximum stereo or amplifier output) knowing only the speaker Ohm rating.
Both copper wire and copper clad aluminum (CCA) wire charts are provided. Because aluminum has a lower conductivity than copper (higher resistance per foot), the length will be shorter than for real copper.
Note: Be sure to check my additional tips further below as they can help you save money.
Choosing a speaker wire gauge for long distances
What if you need say 50ft or even 100ft of length? In that case, a general rule of thumb is to double the size by choosing a wire thickness 2 sizes up from what you would use for shorter distances.
The gauge number (the electrical conductor size as per wire standard charts) increases or decreases by an even number (by adding or subtracting 2) as odd numbers aren’t commonly used.
Example: 18AWG wire will lose about 4 watts at maximum power if it’s 50ft long. To avoid this when moving from a shorter wire length, we can pick a speaker cable 2 sizes up: 18 AWG -> 16 AWG -> 14 AWG.
Tips on using smaller speaker wire and saving money
As real copper wire is more expensive these days and because most people don’t drive speakers at full power, here are some tips to keep costs down:
- If you rarely use your amp or stereo output above 50%-60% power, you can go down one wire AWG gauge. This is because you’ll never reach the wire’s current capacity if you don’t use maximum power.
- Have extra wire you’d like to put to good use? You can double-up or even triple-up smaller gauge wire to get the same gauge as a thicker wire size. (Example: using two lengths of 18AWG you have lying around in parallel to approximate 16AWG wire).
- For surround sound and center channel home theater speakers, you shouldn’t spend a lot because their power needs are usually fairly low.
Is oxygen free speaker wire worth it?
No, oxygen free pure copper wire will not deliver any noticeable improvements in sound or power. It’s not worth spending more money on it.
It’s a great marketing feature for retailers but the data shows that there’s 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.
The electrical signal will not have any measurable difference at the speaker end.
It is true, however, that real copper wire is better than copper coated aluminum wire as I explain later.
What gauge is speaker wire? (Wire size and wire gauge explained)
Speaker wire doesn’t have just one size (gauge) – it’s standardized and based on the American Wire Gauge (AWG) chart which lists standard sizes using a number.
Less commonly known as the Brown and Sharpe wire chart, the American Wire Gauge chart has been around since 1857. It specifies sizes, each with a given circular area of the electrical conductor size, its resistance per foot or meter, and some other specifications.
Likewise, each AWG wire gauge has an electrical current capacity (how many amps it can handle, also called ampacity sometimes).
The AWG wire chart uses a numbering system in which thicker cable has a smaller number. Likewise, a larger number is used for smaller wires with fewer conductors.
Speaker impedance and power vs the correct gauge wire
When an amplifier supplies an audio signal with a given voltage output, speakers with a lower impedance draw more electrical current (higher amps) than higher impedance speakers. This can make a difference in the wire size you need based on the length and power carried to audio speakers.
Higher amps require a larger conductor size (thick wire) just like for power wire. By comparison, thicker speaker wire has low resistance and therefore less power lost across it at high power levels or a long cable run.
Most speaker wire sold today is made up of two conductors attached as a pair with one marked as the positive; they’re essentially the same as stranded power cable paired together. The gauges available range from about 20 gauge to 10 gauge, with 18 gauge being one the most popular.
Thin wire such as 20AWG or 22AWG isn’t very common but occasionally can be useful for lower power speakers.
Stranded vs solid conductors
All speaker wire sold is stranded, meaning it’s made up of a bundle of 16-60 or more very fine copper conductors. Solid wire, however, has only one conductor. In terms of audio, it’s fine and the sound quality is the same.
You may have heard of the skin effect in some conductors which becomes more of an issue at higher frequencies but that’s well above the 20 to 20kHz audio range so it’s not something to worry about.
Stranded speaker wire design
For stranded types, a thicker wire gauge uses more conductor strands with each strand being larger than those in a smaller gauge wire. Some types simply use more very fine strands to enhance flexibility during use but will still maintain the same total conductor cross area and current carrying capacity.
Why stranded speaker wire is preferred over solid
Stranded wire has a big advantage over solid in that it’s very flexible and not prone to breaking under stress. It’s also easier to strip the insulation to bare wire with a wire stripper. It’s also easier to work with if using spade connectors or inserting it into a crimp connector.
Since solid core is used for home and industrial electrical wiring, you might be tempted to use some leftover house electrical wire for your speakers. There’s no technical reason you can’t use it for audio but smaller gauge solid wire can develop stress cracks over time due to vibration in installations like a vehicle, for example.
Solid core wire isn’t easy to deal with in situations where you’ll need to go around curves like around car seats or tight spaces.
How much wire do you need?
Buying & using speaker cable is definitely one of those cases where the old advice “better to have too much than not enough” applies! You don’t want to run out because you didn’t plan ahead.
It’s always best to measure and be sure – and overestimate what you need to be sure you don’t run short.
To figure out how much speaker wire you need, my suggestion is to use one of the following:
- A tape measure
- A long length of string to run
Be sure to try to take curves & bends into account but don’t worry about getting it exactly right. Measure the distance and then add a few feet (an extra 2 feet or so is good) to account for curves and other little things that add up.
A tape measure works well and so does string or rope you can place along the path where the wire will go.
Mark the length, then measure it. I like to add at least 1 foot of length for each wire section for home stereo use and 2 feet each for car stereo installations to play it safe.
Figuring out how much wire to buy
When it comes to buying speaker wire, one thing to know is that it adds up fast! Here are two examples to show what I mean:
Home stereo example:
- Front speaker lengths measured: 2 x 6 ft
- Rear speakers measured: 16 & 22 ft
Total wire needed: 6 + 6 + 16 + 22 = 50 ft (15.2m)
Car stereo example: Running wire from the dashboard head unit to front door speakers and to rear deck speakers.
- Front speaker lengths measured: 2 x 8 ft
- Rear speakers measured: 16 & 20 ft
Total wire needed: 8 + 8 + 16 + 20 = 52 ft (15.9m)
Speaker wire is normally sold in rolls such as 25ft, 50ft, and 100ft, although some retailers offer it by the foot as well.
Precut lengths are also available sometimes, too. Those are usually around 6, 12, or 18 ft. However, more often than not you’ll save money by buying a good quality by the roll.
**Rember this rule: never take chances with speaker wire length – don’t guess. Buy at least a little bit more than your estimate.
Copper-clad aluminum vs copper speaker wire
Copper-clad aluminum (CCA) wire has, in the last few years, become more and more common as the price of copper has gone up. It’s one of those “little things” you might not know when buying that companies aren’t telling you.
Unlike pure copper wire, copper-clad aluminum uses an aluminum wire core with a thin copper plating. From the outside, it misleadingly looks the same because of the plating.
Aluminum offers a lighter weight and lower cost than copper, so at first it may seem like a great way to replace the more expensive copper options. However, there’s a problem.
Aluminum has only 61% of the conductivity of copper (in other words, it has 39% more resistance) meaning it will take larger aluminum wires to get the same power handling, capacity, and resistance value.
Everyday use & what to know
In most cases like average listening & typical power levels, it’s not really a problem in day-to-day use. However, if you’re going to drive speakers at higher power levels or want the absolute best for your money, you’ll need to be sure to look for packaging that specifies the wire is 100% pure copper.
To get the same performance as true copper wire when buying CCA speaker wire, move up one gauge in size. For example, to replace 18 gauge copper wire, use a 16AWG or 14AWG CCA wire.
It’s also worth mentioning that this type of wire is less flexible than pure copper and aluminum can potentially break if repeatedly flexed.
Thank you very much Marty, meticulous information of speaker wire and gauge,
it has been confused me to choose correct gauge of wire
I am TH Teh from Penang, Malaysia.
Hi TH Teh. Thanks for the comment & enjoy your weekend! :)
Very helpful. Would you be available for a chat or call consultation?
Hi John & happy Friday! That’s possible, although I certainly don’t mind answering questions you have by email as well. You can reach out to me directly via my Contact page which also has my email address.
Best regards!
Perhaps you’d want to mention that CCA is aluminium and therefore likely to break strands if flexing, especially during your installation.
Thanks for the suggestion, Mark. I’ll look into this more and see how to best mention that.
Absolutely 💯!! There’s also the matter of the corrosion inherent to CCA wire. If it was equal or superior to pure copper these sellers wouldn’t go to the lengths they do to hide the fact that it’s CCA. Like almost everything, you get what you pay for!
You raise a great point, Rodney, so thanks for the comment. I’ll need to mention something about using that type of wire outdoors and for marine use for that reason.
With CCA wire becoming so common I can see how it can lead to problems. Best regards!
The chart is absolutely wrong and misleading, 4mt copper cable for a 300W rms power suggests me a 16 awg cable, what a joke!
Happy Tuesday, Antony. I’m sorry to see that for some reason you feel like it’s incorrect. It’s not wrong and certainly not misleading; I’ve gone to great lengths to make it more accurate and practical than other wire size guidelines out there based on hard data.
Speaker wire quality, size, strand count, and so forth will vary from manufacturer to manufacturer, but we can use typical examples as a good and relatively accurate foundation for mathematically validating wire recommendations.
Power, current, voltage, are critical for calculating wire size we need for any type of electrical load – including the speaker Ohms load. This is one reason why power companies can use high-voltage power lines to distribute thousands of Watts using smaller wire gauge while reducing wire cost power losses over long distances.
As you didn’t include the speaker impedance (this is very important!), I gather it’s 4 Ohms based on the 16AWG result you referred to. I’ll go through this example and validate it using an engineering approach.
Problem: Calculate power loss for 16AWG stranded pure copper wire, 4 meters length, into a 4Ω speaker load with a maximum of 300W RMS power delivered. Determine if 16AWG stranded wire is acceptable.
(1.) Using a typical and reasonable example, we can use 16AWG stranded copper wire with 19 strands of 29AWG wire (“19/29”). Resistance per meter is rated at 0.0147Ω/m. [1]
(2.) Calculate the (approximate) current, in Amperes, delivered to a 4Ω speaker load at 300W RMS:
• Using the power formula P = V^2/R = I^2*R, we get: 300W = I^2*4Ω = I = SQR_ROOT(300/4) = 8.66A.
(3.) Using the amperage from (2.), calculate losses across 4 meters of 16AWG stranded wire at maximum power (maximum current):
• The current flows through two conductor sides (positive & negative) for a total of: 2*4m*0.0147Ω/m = 8m*0.0147Ω/m = 0.1176Ω total resistance for 4m of 19/29 stranded wire.
• Power loss at 300W RMS: P = I^2*R => (8.66A)^2*0.1176Ω = (74.9956)*(0.1167) = 8.75W lost across 16AWG wire at maximum power.
(4.) Check the ratio of power loss across the wire vs power delivered to the speaker at 300W:
• P_speaker = P_amp – P_wire = 300W – 8.75W = 291W
• Power loss ratio (wire to speaker) = 8.75/291*100% = 3.0%
So as you can see, this fits the 5% maximum wire loss guideline I mentioned in the article, and 16AWG is perfectly acceptable if we consider a 5% loss maximum acceptable. Bear in mind that unlike DC power, musical power is dynamic and will NOT see a constant loss/heat as you’d get from a direct current (DC) load.
This means that in practical terms, you’ll won’t have a continuous 8.75W dissipated across the wire at full power (unlike say, for example, powering a DC motor). If you prefer closer to 0% wire loss, you can move up 1-2 wire gauge sizes.
Anton, many of the “rules of thumb” in the car stereo world are not based on actual engineering proof but unfortunately arbitrary recomendations without data to back them up. I know, because I’ve been an installer for many years and a lot of “common knowledge” is wrong.
What values did you end up with? I’d be happy to look at your calculations and we could compare values if you prefer. Or if you need clarity on current, power, wire conductivity, and etc.
Have a good week.
Notes:
[1] Calmont Wire & Cable manufacturer, “Solid and Stranded Conductor AWG Chart”.
[2] Wire strand count based upon my measurement of common stranded speaker wire found in retail stores, used as a median guideline for conductivity, strand count, and total conductor size.
Hello Marty, impressive representation chart.
I have a question with the answer that I already know, but I need your professional retrospect suggestion on my situation.
Long story short, I originally purchased in 1987 a Technics sound system that came with the rest of the Technics equipment, for example: record player, cassette deck, tuner, amplifier, equalizer and the speakers. I had that sound system ever since and loving every minute of it (little pun from Loverboy :) ).
My cables have become brittle and broken, I’ve used many of different styles over the years but never to come to a reasonable conclusion.
About the speaker wiring gauge:
1. my speakers are Technics SB-2641 (connectors at the back are straight pull down/push-in red/black)
2. 8 ohms
3. 200 watts max.
My amplifier is a stereo integrated amplifier SU-V75
As for the wiring there are so many options but for the main use for me would be to have 6-10 feet max length of cabling not more.
Your recommendation would be greatly appreciated.
Marc
Hi Marc. Yeah, I know the Loverboy song well having listened to classic rock for years, ha ha.
Ok, well using my calculator 100W/channel into 8Ω at about 10 feet requires only 20AWG wire (copper) or 18AWG (CCA wire), with no more than 5% power loss at max. power. So you can use 20-18AWG if you like.
Sometimes it’s worth thinking about whether or not you’ll upgrade power in the future and may be get 1-2 gauge sizes higher now. Otherwise, you should be able for find very reasonably priced 20-18AWG wire, maybe 25ft standard lenth. Personally I am not a fan of CCA wire because it’s less flexible in many cases.
Best regards!
Hi Marty, maybe you can help me. I have a 4 ohm mono amplifier 235 watt RMS and 2 parallel outputs for speakers. I am planning to install 2 8 ohms speakers 100 watt RMS each. One will have a cable length of 16 feet from the amplifier and the other one will be 65 feet. What would câble size would you recommend? I am planning to set the volume near 50%. Thanks.
Hi Roger. Knowing the power will be shared evenly between the two 8Ω speakers, I used 235W RMS/2 channels x .5 = about 60W to each speaker at ~50%.
Based on my calculator and the specs you provided, that would be:
• 14AWG copper or about 12AWG CCA wire for 65 feet in length.
• About 20AWG coppper or 18AWG CCA wire for the 15ft length.
If you’re able to get a decent price for a bulk roll of 14AWG wire of course you can just use one size for it all. Best regards!
Thanks alot for this illustration 🤩
Thanks, Mohamed! :)
I have two Sony 6 ohm speakers I am placing 12 ft from the amplifier tuner that is putting out 100 watts per Channel RMS. What size wire do you think I need pure copper? Thanks
Hi Ken. Have you used my calculator? It will provide a good recommenation and you can also change the values to see how it would affect wire size. https://soundcertified.com/what-size-speaker-wire-guide/#SPEAKER_WIRE_GAUGE_CALCULATOR
I created the calculator so people can find out easily. Best regards.
What are your thought about Pure Copper Wire for + (Red terminal) and CCA wire for – (Black terminal? I see them selling in shopee. Do we really need copper for the return wire?
Hi there. It’s strange that one wire would be copper and one CCA. The CCA wire will have a lower conductivity/higher resistance than the pure copper wire unless it’s larger than the copper side by 2+ wire sizes.
It’s technically ok to use it, but it doesn’t really make sense to mix conductor types like that. Basically, the CCA wire will be the side that could reduce power/current delivered to a speaker depending on the power supplied & the speaker impedance.
Having copper conductors on just one side doesn’t make sense because the current in = current out. If you have a link I’d be happy to have a look.
Have a good weekend!
Disagree with oxygen free not producing any noticeable sound differences.
I have older speaker wire on some newly built speakers, 16 awg. RCA regular / RCA Digital, and can hear a notable difference.
There is slight harshness in the mids for the first RCA regular(darker color, more oxygen) and sounds unrestricted.
The second “RCA Digital” (less oxygen, light color) cleans up the mids but sounds a little restricted on some content and not so open sounding. A little harder to setup with sound fields and EQ.
Every movie sound track is different and the RCA Digital sounds great for all music though.
I still have to change my internal mid/woofer wiring, it is only temporary until I get more fire rated wire.
So it may sound slightly different, still yet.
Hi Kevin. I appreciate you dropping by as well as having an opinion to share.
If it’s enough to be heard, it’s enough to be measured, so I’d have to see actual test data in order to be convinced it provides any sonic benefit. In principle, this should be impossible for the most part (assuming, of course, no other variables are introduced into the audio system under test, wire used for comparison is of similar quality, etc. etc.).
I’ll need to find the data I’ve seen as unfortunately I’ve misplaced it. But if you’re happy with what you have and are enjoying your music, all the best to you!
Yep, there are many, many things that influence sound quality so I definitely agree about how things may sound different. Have a great weekend.
Searching for details in sound systems is like chasing ghosts. :)
Is there a specific type or type of cable for the tweeter? I’m asking for this reason. I have a distortion problem in high-pitched sounds that I cannot fix. I tried many tweeters. It happens in all of them. I also try it in different amplifiers. I use thick cable. Does the thin cable make a difference? Could something like a magnetic field affect it?
Hello Burak. It really should not matter for the tweeter as long as the wire is decent quality and of adequate size. The thin cable is not likely the problem unless it is extremely small.
If you have distortion it sounds like an issue with the audio source at some point. One thing you can try is using only a few components (amp, speakers, etc.) and a different audio source to see if the distortion goes away. If so, you’re probably having a problem with the source unit or audio media you’re using.
I have a subwoofer which has high-pass filters that then feed the small speakers. If the stereo is 50W per channel, how much of that power can I expect is above the cutoff frequency? It would seem I would be able to use small diameter wires since not all of the 50W gets through the filter.
Hi Bob. If both the subwoofer and small speakers are using crossovers, in principle both could receive up to 50W. However, realistically subwoofers require more power to get the same decibel level (volume level) as smaller speakers.
So *generally* you can often use a lower speaker wire gauge on the smaller speakers if you like. I wouldn’t go too small however. Best regards!