If you know about the standard 6-string electric or acoustic guitar, chances are you’re also familiar with the bass guitar. These two instruments are often thought of together as two of the 3 primary instruments that make up a rock or jazz band (electric guitar, bass guitar, drums).
There aren’t any rules when it comes to this kind of thing, it’s kind of just the way social conventions have evolved over time and then people repeat them. The principle plays right into what we’re talking about today, which is why bass guitars have 4 strings.
Bass guitars have 4 strings not for any specific reason or rule, but due to convention. A standard bass guitar is modelled after the upright bass which is from the same class of instruments as the violin, viola, and cello, and these instruments all have 4 strings.
A lot of people may try and wax creative and come up with all kinds of reasons for why the instrument only has four strings, but at the end of the day, it just comes down to the conventions we’ve all gotten used to over time. Bass guitars certainly don’t have to have just 4 strings. They can also have 5, 6, and probably even 7 strings, but at that point, it’s up to you to find a manufacturer who actually makes them that way. Let’s talk more about the reasons.
Why the Bass Guitar Only Have 4 Strings
Bass Guitars Are Based On Classic 4-String Orchestral Instruments

The standard bass guitar like the Fender Precision Bass (which you can find on Sam Ash), as I just previously explained, is modelled after instruments that are much older than the standard guitar (as we know it today) including the violin, viola, cello, and upright bass.
These instruments, in their modern and complete form, have been around since the 16th century, whereas the guitar as we have come to think of it is relatively recent.
Guitar-like instruments have indeed existed for thousands of years, including the notorious Hittite image of a person playing an instrument that looks just like it (Wikipedia link here).
Apparently, the carving is 3,300 years old, but the guitar as we know it today is early 20th century, and the older classical guitar started popping up in the 17th and 18th centuries. The electric guitar, as an aside, was first patented in 1937.
Bass Guitars Are 4-Stringed Out Of Convention

All of this information is up for debate and it depends on how you define the instrument, but the point here is that the bass guitar is modeled after instruments that have existed in their modern form for hundreds of years. The bass guitar has four strings almost purely out of convention to be that way.
If you think about it (and obviously, many others have felt the same way), there’s no reason why a bass guitar can’t have more strings.
These days, it’s a lot more common to find 5 and 6-string bases due to players like Les Claypool, Victor Wooten, and Anthony Jackson, but that wasn’t always the case. With that in mind, there are other reasons why people say that the bass guitar only has 4 strings.
Bass Guitars Serve The Tendency to Play Single Notes

One reason people commonly state why the bass guitar, and bass instruments in general, have four strings is because they’re usually played melodically, meaning one note at a time, rather than harmonically.
Because bass instruments occupy the lower end of what the human ear can actually hear, chords and notes played together in this range tend to sound muddy and indistinct.
The bass line from Daft Punk’s “Around the World” is probably my favourite bass part of all time, and notice how it’s entirely made of single notes.
Compare this to the electric guitar where the notes and chords of the instrument occupy the sweet spot of the frequency range (200Hz to 2,000kHz). We can hear sounds within this range very easily and thus variations in tonal characteristics and pitch are easy for us to distinguish from each other.
Put more simply, you can hear mistakes, nuances, and the tiniest rapid details more clearly than on the bass guitar.
Playing 2, 3, or even 4 notes at the same time on the bass guitar would just sound like a wall of sound with no distinguished tone or pitch unless you’re playing much higher up the neck.
It’s worth mentioning that you certainly can play chords and more than one note at a time on the bass guitar, it’s just that it has become more common to play single notes rather than chords and double stops because the instrument lends itself very well to single-note patterns (more on how to play bass in my guide).
Is A 4-String Or 5-String Bass Better?

More equals better, or does it? A 4-string or 5-string bass may or not be better but a decision like this is ultimately in the eye of the beholder. It’s true that a 5-string has more capability than a 4-string bass guitar, but a 4-string bass might be much easier for a player to start on.
It’s my personal opinion that, for the beginner, it would be best to start on the classic 4-string bass guitar because most bass guitar books, lessons, and songs will use this instrument over the 5-string. Moreover, 5-string bass guitars (at least the good ones) tend to cost more money than 4-strings.
I feel the same way about the electric and acoustic guitar though. 6 strings are enough to learn with when you’re first starting out, so I don’t see the utility in developing your playing chops with a 7-string or even 8-stringed guitar which just adds even more complication to an already sophisticated instrument.
Why Does My Guitar Have 4 Strings?

If your guitar only has four strings, chances are that it’s not a standard guitar but a bass guitar. There are other manufacturers who produce 3-string guitars including Loog Guitars, which is a company that designs stringed instruments for kids.
The idea is that it’s supposed to be a less complicated version of the guitar made especially for young children to learn on. Another reason why your guitar may only have 4 strings is that it might just be missing two. Are there are an additional 2 tuning pegs on the instrument?
If the answer is yes then you might just be missing the other two strings. Get some Elixir polymer-coated strings to fix this problem and make sure to get Elixir for one simple reason that I’ve discussed elsewhere on the site.
Are All Bass Guitars 4 Strings?

Not all bass guitars have 4 strings but the most common models have 4 strings. If a bass guitar has more than 4 strings, it’s most likely to be a 5-string bass guitar, although, 6-string bass guitars certainly do exist.
One of the most iconic players to use a 6-string bass guitar is Anthony Jackson whose picture you can see above.
4-String Versus 5-String Basses for Beginners?

If you’re a beginner at playing bass, it’s best to start with the most common version of the instrument, not because of any kind of intrinsic difficulty – although a 4-string bass is obviously less complicated than a 5-string bass – due to convention and ubiquitousness.
Some of the most popular songs ever written will include a 4-string bass guitar and most bass instructional books will also use a 4-stringed bass as their primary instrument on which to learn.
If you feel super confident about your ability to take on the task of learning a slightly less common version of the instrument, by all means, go ahead, but for most people, starting simply is just the better option.
With that said, there are some pros and cons of playing each, including more capabilities on the 5-stringed bass versus the 4-stringed counterpart as well as the fact that it might save you from having to buy a 5-stringed bass in the future if you’re ready to start learning songs that have one.
It’s better to have something and not need it than not have it and need it.