Q&A for How to Determine What Key a Song Is In

The easiest way is to look for sharp and flat symbols on the top line of the first page of sheet music. These will tell you what key the song is in.

I suggest you listen for the first and last chords of the song. Although this isn't always the case, usually the first and last chord of a song will tell you what key the song is in.

If there are no sharps and no flats, the song is either in C Major or A minor.

You can use the circle of fifths to help you. Each piece will have two keys, for example, C Major is the same as A Minor, as they both contain the same notes. If A seems to be the predominant root in a song in that key, it is probably in a minor key and if C is the root, it is major. However, songs can also switch from minor to major or vice-versa. It's all relative.

Figure out which key the song is played in. Also, look for the sequence in which these chords are played.

If the song is in a major key, then it is in G major. If it is a minor song, it is in E minor.

You would have to look at your key signature and look at the flat next to the last, that would let you know what key you are in.

An internet search can provide you with a pictorial reference. From bottom to top, the spaces in between the lines on a treble clef spells, "F-A-C-E." From top to bottom, the lines are, "E-G-B-D-F," and can be remembered by using, "every good boy deserves favor," as a mnemonic device. To learn what key a song is in, learn the notes within each scale, or count how many black notes the piece of music contains, and use the circle of fifths as stated in a previous answer.

Because you play the piano, it's a bit easier. If your song is in one key, you should just count the amount of black keys you use. Then you should look into using the circle of fifths, for which you can find a lot of resources on on the Internet, to figure out which key you are playing in.

Your ears will ultimately have to figure this out. Most melodies are focused around the major/rel minor scale it is written in. You must start by being able to sing the melody. Then listen for the pattern of notes that most of the notes have in common. This is a very advanced step in music comprehension, so try with an easy song; Mary Had a Little Lamb is a good start. For example, by singing the intro, "Mar-y had a lit-tle lamb" you could also sing 3-2-1-2-3-3-3... here there's a good chance by detecting part of the scale that one could guess the major key. In this case, it would be whatever key you wanted the "1" to be in.