Being able to find out what key a song is in is a very good skill to have as a guitar player. There are a few things that you can work on to start being able to find out what key a song is in. Knowing what major scales sound like and being familiar with what chords are in a given key are two things that can really make finding out what key a song is in easier. This lesson will focus on songs that are in major keys only.
The first thing that you need to be able to do is to pick out the root note of the key of the song that you are trying to learn. When we are talking about the root note of a key we are just referring to the first scale degree or the tonic of the key. For example, the root of a G major scale would be a G note. If you are practicing the major scale on a regular basis and getting that sound in your head, it will be easier for you to focus in on which note is the root of a particular key. When you get used to listening for the root, or tonic, of a scale, your ear will be drawn to that note when you start to hunt around for notes on the fret board for possible keys.
A good exercise to develop your ear is to play a song on your stereo or headphones where you know the key. Play the major scale over that song and listen to what it sounds like. For example, if you like a song and you know it is in the key of G, put that song on and play a G major scale along with it.
Once you think you have found a possibility for the key of a song, you should look at some of the chords that are in the song to confirm your suspicions. Here is where you have to put in some hard work. You really have to study your keys and start to memorize which chords are in each key.
Let’s stick with the key of G major for an example. The chords in the key of G major are G major, A minor, B minor, C major, D major, E minor and F# diminished. This may seem like a lot of information but you will find that the more song you learn, the more you will start to recognize which chords belong to a given key.
In the video we use the song “Time of Your Life” by Green Day as an example. The first chord in that song is a G major. The next chord is a C major. If you look at the chords we listed for the key of G major you will see that the fourth chord is a C major. This is a great hint that we are in the key of G major. D major is the third chord in the progression. Look at the fifth chord in the key of G major. It is a D major. At this point it is pretty safe to say that this song is in the key of G major.
Learning how to find out what key a song is in may be difficult at first, but the more you do it the easier it will become. Make sure to get the sound of a major scale in your head and study what chords are in each key.