Before someone chimes in and says that instruments are in keys, I think of this as mostly a horn and woodwind thing. A lot of horns like the key of F, for example. And, while a guitar’s standard tuning is all notes of C (starting at E), the guitar is easiest to play in E, G, A, C, and D. So I would argue that a guitar isn’t in a specific key like a horn or a woodwind.
But before I go further, let’s figure out what a key is as it relates to music.
What Is A Key In Relation To Music?
A key is basically a group of notes. In Western music, we usually think about major and minor keys. A major and minor key has specific intervals between each degree of the scale that makes up that key.
So, for example, a C major scale, which has no sharps or flats, just goes C, D, E, F, G, A, B, and back to C. The intervals between these notes are tone, tone, semitone, tone, tone, tone, and semi tone back to the C. These intervals are the same for every basic major scale regardless of whether you start on C or E flat.
In Western music, we’re used to these types of intervals and find them nice to listen to.
That’s an extreme crash course in basic intervals. Once you know the rules you can begin to break them, and lots of Western music strays from this. Take a look at all of my articles on musical intervals for more information.
But, to put it basically again, a key is the specific notes that are “allowed” to be played and still sound good. You could play a song in the key of A and then just move every note up a tone to play it in B. It will still sound the same, and you’ll still recognise it as the same song, it will just be higher.
What Keys Are Easy To Play Guitar In?
From lowest to highest string, the guitar is tuned E, A, D, G, B, E. Since none of these notes are sharp or or flat, they’re all in the key of C. So you may think the guitar is in C. While this is kind of correct, you’ll also note that there’s no C there either. And if you just strum all of the strings open, it doesn’t sound very good either. The guitar doesn’t really work without fretting some strings. While if you just play all the white keys on a piano, you stay in C and can make some sort of melody.
Because of the guitar’s specific tuning, it tends to work well in specific keys. If you take a look at the open guitar chord shapes, you’ll notice there are five basic shapes E, A, D, G, and C. You also have E minor, A minor, and D minor. These are often called open chords and are pretty easy to play. Because of this, guitar tends to lend itself to being played in the keys of E, A, D, G, and C. It’s also why a lot of easy guitar songs tend to be in these keys.
Yes, you’ll have to stray from these open chords to play in these keys, but the above keys share so many chords that you don’t have to go very far.
And this is part of the beauty of the guitar. While everything takes practice, most people can pick up the basic guitar chords in a couple weeks and be able to at least play them slowly. This means a lot of people can play a few of their favourite songs quite quickly. They can then get a lot of joy out of playing and improve from there!
What If You Want To Play Guitar In A Less Suitable Key?
You can play the guitar in any key, but it can be slightly more difficult if you go outside of the open chords above.
As you move further along with your guitar playing, you’ll learn barre chords. Barre chords allow you to play chords that aren’t the five open chord shapes (plus the three open minor chord shapes). You’ll notice, for example, that once you learn barre chords, you can play in a key like F quite easily because is also has a lot of the open chords in it.
But beyond F and using barre chords, how else can you play in other keys?
Use A Capo
A capo can be convenient if you’re playing with instruments that are more comfortable in other keys (like horns!). Often it’s easier to adapt with the guitar than it is to make other instruments adapt.
The keys of E, A, D, G, and C also tend to be suitable for mid-range male voices. Female voices and lower male voices can sometimes have difficulty in these keys, so it may be worthwhile using a capo to play in a different key that compliments a singer’s range better. In this way, you can just put a capo on a guitar a few frets up and play the same shapes on a chord chart. The song will still sound the same, just higher.
And That Should Answer Your Question
For those with more experience in music theory, I’m sure this article has come off as very broad and fairly basic, but that’s kind of the point here. I’ve made the assumption that the audience for this article is a beginner so I’ve tried to make this article as accessible as possible. If you’re a beginner, hopefully this was a good explanation for you! It’s just a brief taste of music theory, but there’s plenty more to learn and understand.
As mentioned, the guitar isn’t really in a key. Sure, the strings are tuned to notes that are in the key of C, but the open strings also don’t contain a C. Sure, C is one of the five keys that the guitar is more comfortable in, but it’s also comfortable in a lot of other keys to0.