What Is A Key On Guitar? Guitar Keys Explained

Guitar Keys Explained

One of the first steps to understanding music theory on guitar, is learning about keys. So what exactly is a key on guitar?

A key denotes the root of a scale that a group of given chords or notes fall into. For example, if a song begins on a G chord, and then transitions to C and D chords, before returning again to G, this song would be in the key of G. For soloing purposes, this means a G major scale could be used to play or sing over the song.

Once you understand this, some other logical questions emerge, like how do you figure out what key a song is in? We’ll answer that question and some other common questions about guitar keys in the sections below.

How Do You Know What Key A Song Is In?

One of the quickest and easiest ways to figure out a key of a song, is to determine the chord that the song begins and ends on. Remember in our example above, where the song began and ended on a G major chord? One could quickly conclude that the song was in G major, or at least that the G major scale could be an appropriate choice for playing a guitar solo.

Is Learning Guitar Even Worth It? (... x
Is Learning Guitar Even Worth It? (The TRUTH)

However, this method isn’t completely foolproof, as some songs don’t begin on the chord of the key that they’re in. If you use this method and the key still doesn’t sound correct, you can look up a tab or chord chart on sites like Ultimate Guitar for help.

Why Do Guitar Keys Matter?

You may also be wondering why it even matters what key a song is in. To be fair, you don’t absolutely have to know what key a song is in in order to play it. If all you want to do is play the chords of the song, then all you really need to know is those chords – and what key it’s in is not a huge concern.

Guitar keys become a lot more important, however, if you want to play a solo or improvise over a song, or if you’re trying to learn a song by ear. If you’re doing any of those things, they become a lot easier once you have the foundation of knowing what key you’re in. If you don’t know the key, you’re at the mercy of trying to improvise over each chord individually, rather than having an overarching scale that will work over the whole song.

Guitar Keys Explained

Each key has it’s own 7 notes, and also contains a variety of chords that can be used. When someone uses the phrase “playing in key” or asks what key a given song is in, they’re referring to the “tonal center” around which these chords or notes of a song are based in.

To learn how notes and chords go together to form a key, I recommend Marty Schwartz’s excellent YouTube videos. They’re very practical and don’t bog you down with unnecessary music theory. Here’s a great one to get started:

Ready to Get Better at Guitar, Faster?

Whenever you’re ready to take your guitar playing to the next level, check out my favorite resources below:

Best Strings

Elixir Nanoweb Acoustic Guitar Strings

  • Unique polymer coating allows strings to last for months or years at a time, making for an exceptional value.
  • Provide the perfect mix of boom, range, twang, and brightness that acoustic music is known for.

Best Guitar

Martin D-18

  • Beloved by everyone from Paul Simon to Gordon Lightfoot, the D-18 is one of Martin’s most legendary guitars ever.
  • An excellent, premier quality acoustic guitar for bluegrass, country, folk, rock and more. This is what I play myself.

Free Guide

Chords, Tabs & Lessons for 100 Songs

  • This free guide from Acoustic World gives you chords, tabs, and video lesson for the 100 best songs to learn on guitar.
  • I spent hours putting this together all by myself to help you get better at guitar, faster!

Free Book

Fingerpicking vs Flatpicking Guitar

  • Learn which picking style is right for YOU by exploring examples, history, and popular players of each style.
  • Discover essential techniques and pros and cons of each approach.

Corbin Buff

Corbin has played guitar for over a decade, and started writing about it on Acoustic World in an effort to help others. He lives and writes in western Montana.

Recent Posts