Wondering what size speaker wire you need? You’re not alone – there’s a lot of confusion when it comes to hooking up speakers & getting the right type and gauge of wire.
In this guide, I’ll show you the right gauge and type of speaker wire you’ll need. I’ll also cover a lot more, too:
- What speaker wire “gauge” means
- How to check which speaker wire is positive or negative
- How to connect speaker wire to terminals or splice it
- Copper clad aluminum (CCA) vs pure copper wire
Read on to learn more!
Infographic – Speaker wire fast facts
Quick answer: What size speaker wire do I need?
First and foremost, it’s important to know that you shouldn’t spend money on bigger speaker wire than you need.
It’s a waste of your hard-earned money to get wire that’s bigger (and costs more) than what you need. It won’t improve the sound or anything like that, despite what salespeople may tell you.
The size of speaker wire you need is based on 3 things you can easily check:
- Your stereo or amplifier’s power output (usually listed as watts “RMS”)
- The Ohm rating (“impedance”) of your speakers
- Length needed
However, if you’d like a simplified answer here’s a chart to fit the needs of most people.
Simplified speaker wire size chart
|Wire Size||Recommended For|
|18 Ga.||Car and home speakers up to 25 ft with average power levels (50W RMS and below)|
|16 Ga.||Longer speaker runs for car & home stereo speakers; Moderate power subwoofers (under 225W)|
|14 Ga.||Long (100ft+) speaker runs or higher power applications such as high-power 2 or 4 ohm subwoofers.|
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 handling as it’s usually priced well and easy to find.
Choosing speaker wire for long distances
The table above works well for most cases. But what if you need say 50ft or even 100ft of length? In that case, you’ll want to double the size by choosing a wire gauge 2 sizes up.
Wire gauge (the amount of copper in them) doubles by moving to not the next gauge, but instead the one after that.
18AWG wire will lose about 4 watts at maximum power if it’s 50ft long. To avoid this, we’ll pick a wire gauge 2 sizes up: 18 -> 16 -> 14 gauge.
Speaker wire power & size chart
If you’d like save money by using a smaller gauge wire here’s a handy chart I’ve made based on the maximum power you can use with wire for different lengths. With it, you can pick the right wire based on your type of speaker, how much power you’ll use, and one of several close lengths you may need.
|Wire Gauge||Length/Power for 8 Ohm Speakers||Length/Power for 4 Ohm Speakers||Length/Power for 2 Ohm Speakers|
|20AWG||3ft: 263W, 16ft: 49W, 25ft, 32W 50ft: 16W||3ft: 131W, 16ft: 25W, 25ft: 16W, 50ft: 8W||3ft: 66W, 16ft: 12W, 25ft: 8W, 50ft: 4W|
|18AWG||3ft: 418W, 16ft: 78W, 25ft: 50W, 50ft: 25W||3ft: 209W, 16ft: 39W, 25ft: 25W, 50ft: 13W||3ft: 104W, 16ft: 20W, 25ft: 13W, 50ft: 6W|
|16AWG||3ft: 664W, 16ft: 125W, 25ft: 80W, 50ft: 40W||3ft: 332W, 16ft: 62W, 25ft: 40W, 50ft: 20W||3ft: 166W, 16ft: 31W, 25ft: 20W, 50ft: 10W|
|14AWG||3ft: 1056W, 16ft: 198W, 25ft: 127W, 50ft: 63W||3ft: 528W, 16ft: 99W, 25ft: 63W, 50ft: 32W||3ft: 264W, 16ft: 50W, 25ft: 32W, 50ft: 16W|
|12AWG||3ft: 1679W, 16ft: 315W, 25ft: 202W, 50ft: 101W||3ft: 840W, 16ft: 157W, 25ft: 101W, 50ft: 50W||3ft: 420W, 16ft: 79W, 25ft: 50W, 50ft: 25W|
For example, a 2 Ohm car subwoofer with up to 250W of power from an amp but only needing 3ft of length can use 14AWG wire. (Instead of a larger, more expensive wire)
What gauge is speaker wire?
Speaker wire doesn’t have just one size (gauge). Most speaker wire follows the American Wire Gauge (AWG) standard that uses a chart of different gauges. It assigns a number to each standard size & electrical conductor rating. Likewise, each size is rated for a certain amount of electrical current capacity.
Speaker wire comes in a wide range of standard sizes based on the American Wire Gauge (AWG) standard. The American Wire Gauge standard, also less commonly known as the Brown & Sharpe wire gauge, is a standardized wire gauge system used since 1857 for the diameters of round electrically conducting wire.
AWG wire charts use a numbering system where a smaller number is larger wire with more copper conductors. Likewise, a larger number is used for smaller wire with fewer conductors. I realize it seems kind of odd, but once you start using it you’ll get used to it pretty quickly.
Why wire gauge matters
The AWG is very important because it means you can be sure what size of speaker wire you’re getting just like any other power wire you’d buy. Speaker wire is treated the same (since it is the same, basically!) as regular power hook up wire which also follows the AWG standard.
Most speaker wire sold today is made up of 2 wires attached as a pair with one marked as the positive wire (I’ll cover this later here). Gauges available usually range from about 20 or 22 gauge to 10 gauge, with 18 gauge being the most popular.
Stranded vs solid wire
Solid wire (left) is a terrible choice for speakers & audio systems. It’s very hard to bend & curve, it can break when exposed to constant vibration, and it’s also harder to make connections with. Stranded wire (right) is tremendously easier to deal with. Stranded wire is made up of a large number of tiny copper wire strands, making it very flexible and also easier to strip, crimp to connectors, and work with by hand.
All speaker wire solid is stranded wire – meaning it’s made up of a bundle of 16-60 or more tiny copper stands. It’s very flexible and also easy to deal with for stripping the wire & adding connectors or twisting it by hand. Solid wire, however, has only one conductor.
Since it’s commonly used for home & industrial electrical wiring, you might be tempted to use leftover solid wire for your speakers. Solid wire is a terrible choice for nearly all audio systems and especially car audio installations. But why?
Use stranded, not solid wire for speakers
Solid wire is fine for homes or buildings since it’s never moved once installed. However, it’s very hard to bend into place and is also subject to damage over time when exposed to constant vibration like in a car or truck. Over time, the wire can develop weak spots which break!
I strongly recommend you don’t bother with solid wire as it’s not worth the risk or hassle. Many kinds of solid wire (like for home outlet wiring) have insulation that’s super hard to strip, too.
How much wire do you need?
It’s always best to measure to make sure – but since many people use speaker wire for almost the same things there are some common lengths that work. In the diagram above you can see some common lengths for speaker wire that should be in the “ballpark.”
Buying & using speaker wire 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 of wire because of not planning well.
To figure out how much speaker wire you need, my suggestions is to use one of the following:
- A tape measure
- A long length of strength 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 (2 or so is good) to account for little differences.
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:
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. Just be sure you don’t buy poor-quality wire or overpriced wire (more about that later).
Just remember this rule: never take chances with speaker wire length – don’t guess. Buy at least a little bit more than your estimate.
Which speaker wire is positive? Which is negative?
How do I check if a speaker wire is positive or negative?
The most common kinds of positive wire markings are shown here as examples. 99% of the time, figuring out which wire is positive is really easy once you know what to look for.
The good news is that once you know what to look for, 99% of the time it’s very easy to tell which speaker wire is positive and which is negative.
Here’s a list of the most common positive speaker indicators:
- A printed line or series of lines is on the positive wire
- One wire’s insulation is red or a different color than the negative wire (most often red is used)
- One wire has a copper color and one has a silver finish
- The positive wire may have small “+” symbols and/or wire gauge info printed on it
- An imprint or molded stripe is made in the positive wire’s insulation
Of the 5 kinds, imprints can occasionally be a little bit harder to notice so sometimes you need to look very closely under good lighting. Also, positive wires that use a “+” print can be a little hard to read sometimes, too.
Which is positive: copper or silver?
These are less common, but of speaker & power wires that have a copper and a silver color, you can pick one of the two to be positive. However, as a rule the copper wire is treated as the positive.
The “silver” wire is actually copper wire that’s been lightly coated (“tinned”) in most cases.
Once you know which is the positive wire then the other is the negative wire. Music uses alternating current (AC) signals and doesn’t flow in only one direction. We use one wire as the positive one when connecting speakers to be consistent when connecting them.
That’s to avoid having some speakers wired “out of phase”, which just means speakers playing with the opposite motion as the others which results in poor sound. It’s important to be sure to connect your speakers all the same way for best results.
How to cut and strip speaker wire
Examples of the most common wire stripping & cutting tools. A wire stripper can cut & strip most wire while a crimp tool can strip and also crimp connectors for wire. Wire cutting pliers are very handy for cutting small to large wire. Automatic wire strippers make stripping wire super easy.
There are a number of affordable tools for cutting or stripping speaker wire. All of the tools pictured above can cut and strip wire. If you’re using crimp connectors, a crimping tool is best.
For the easiest possible remove of wire insulation, automatic wire strippers, available from about $15, are wonderful and make the work super easy to do.
Expect to spend about $7-10 for the basic hand tool you need.
How to splice & extend speaker wire
Splicing speaker wire isn’t very hard and there are a few ways to go about it. However, I do not recommend just twisting wire together. It’s unreliable and will come apart over time.
You can also potentially damage your stereo or amplifier if the wire becomes exposed and creates a short circuit.
Instead, here are 2 ways you can splice speaker wire with professional results:
- By soldering and insulating
- Using crimp connectors
Soldering is a bit harder to do, but the benefit is it’s the most reliable way to connect wires. You’ll need a soldering iron (at least 15W, although I recommend a 25W or higher one), solder, electrical tape, and a tool to strip the wire.
A crimp tool (left) is often affordable and easy to find. Some include crimp connectors. Blue crimp, or “butt” connectors (right) work well for splicing the ends of speaker wire.
Crimp connectors are reliable and easier to use, too. It’s a simple as stripping the speaker wire, twisting the wire strands tightly, then inserting them into the connector and then crimping it tightly on each end.
A crimp tool can be found for under $10 if you shop carefully.
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 wiring 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 it’s at first glance it may seem like a great way to replace more expensive copper wiring. However, the problem is that aluminum isn’t as good of an electrical conductor as copper.
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 wire quality.
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 be sure to look for packaging that specifies wire is 100% pure copper.
When buying CCA speaker wire, to get the same quality as true copper wire move up one gauge in size. For example, to replace 18 gauge copper wire use a 16 gauge CCA wire.
Wondering how to wire up your home or car speakers and need examples? Check out my speaker wiring diagram article here for more info.
For help installing a car amplifier & speaker, you’ll find some great information in my guide showing you how to wire a 4 channel amp to front and rear speakers here.
Got comments or questions?
I’d love to hear from you, & your questions can help me make this guide better! Feel free to leave a comment or question below.