How To Identify The Key Signature Of A Song

After reading this page you’ll have a little hands-on experience at determining the key signature of a song. This is a skill you’ll develop with time as you learn more and more about how music works, but you’ll get a firm understanding of what to look for right here, right now.

There are up to 24 possible key signatures. Since there are 12 tones in music, there can be 12 major keys and 12 minor keys.

In the exercise on this page we’re going to practice identifying the key signature of a song. Before you try it, be sure you know the difference between the sound of a major chord and the sound of a minor chord.

Beginning And Ending

Usually the chord that starts a song will tell you what key a song is being played in. Most songs begin and almost always end with the chord that is the same as the key signature. For example if a song begins with an A major
chord, then it’s most likely in the key of A major–but especially if it ends with an A major chord as in the case in the audio example below:

Here is the chord progression that was played: A , D , F#/Gbm , E , A

Exceptions

While most songs begin and end with the chord that is the same as their key signature, there are exceptions Sometimes a song will start on a chord that is not the same as it’s key signature, but the key signature chord will soon follow it. The chord that is the same as the key signature will usually played more than any other chord. Take a listen to the example below:

This song is in the key of F (F major). Yet it begins with an A#/Bb chord. Here’s the first part of the chord progression: A#/Bb – C – F – A#/Bb – C – F. Clearly it ends with an F chord, and usually this is a dead giveaway.
But the bridge that comes next leaves no doubt: Am – Dm - Am – Dm – A#/Bb – C – F. It also ends with and F chord. The lesson learned here is that the beginning may be a little vague, but the ending of a song or chord progression in a song will usually leave no doubt as to what the key signature is.

If a song doesn’t end with the chord that is the same as it’s key signature it usually leaves a feeling of “hanging”. It’s like the song isn’t complete without the key signature chord at the end.

There are songs that end on a chord other than the key signature chord. You can usually spot them a mile away. Some artists use them to create that incomplete or hanging feeling at the end of a song.

You’ve Got To Train Your Ears

You best bet for learning how to determine a song’s key signature is to practice. In fact, it’s the only way you’ll every truly know. Your ears have to be trained to know what to listen for.

Try listening to the radio with your guitar in hand and try to figure out the key signature for each song that plays. First listen for a major or minor key and then try to determine the name of it’s key.

If you know your E shape barre chord and your E minor style barre chord then you can just go up and down the neck using your 6th string as a reference, playing chords until you’ve found the right one.

Final Thoughts

A lot of times (but not always) a song will begin and end with the chord that is the song’s key signature.

Another way to look at it is that the chord used most in a song is the same as the song’s key signature. There are 12 major keys and 12 minor keys.

The best way to develop skills in identifying key signatures is by listening to songs and trying to identify their key signature by ear. Pick up your guitar
and try to identify the roots of the chords being played in the song. Use your low E string to find these root notes.

Another thing you can do is visit the Chord Progressions section of this site and look at the common scale/chord systems used in songs.

With a little practice you’ll easily be able to identify a song’s key signature.

To play solos over a song you first need to identify it’s key signature, then you will be able to pick the appropriate scales to solo with.

The easiest way to look at this is that with a major key song you use the 5 basic major scale patterns to solo with and the basic minor scale patterns
for a minor key song. In most cases, though, you can use the basic minor scale patterns to solo over a major key song, too. This is very common in blues and rock music.

In the Scales section of this site you can see the 5 basic major and minor scale patterns. Each pattern has a root note. The root note is what
you match to the key signature. For example: for a song in the key of A, you could use the major scale patterns where the roots fall on the A note.