Piano Scales - How to Find The Scale of a Melody

by Arvind Padhiar

Hi Dear, I would like to know how to find out the scale of a melody, and how to match chords with any melody. Thank you. I am a beginner piano player.

Maria’s Answer:

If you read sheet music, you will easily find out the scale of a melody (also called “key”) by looking at the sharps, flats (or lack thereof) at the start of the piece, right after the G-clef and the F-clef. This is called the “Key Signature”.

The key signature gives us two alternative scales; a major scale or a relative minor scale. To be sure, we need to look at the last note of the piece, usually in the bass. This is the “Tonic” of the piece or the “home” where it sounds best to finish.

Let’s take an example:

If you see no sharps or flats in the “key signature”, the key is either C major or A minor. If the last bass note is a C, this confirms that the piece is in C major. If it is an A it is in A minor.

The melody of the piece may go through many different changes and tonalities, but in so-called “tonal” music (major and minor), most music finish on the “tonic”, because it sounds most like “home”. Read more about Key Signatures here.

So what about when you are playing by ear and have no sheet music?

Well, first of all, you need to pick out the melody, of course, so you can play it.

Then, you “line up” the notes that are used at least in a part of the melody; the best would be towards the end of the piece. Line the notes up from lowest to highest. Any black keys?

Find the note that sounds best to finish the whole piece on.

If this is the last note of the melody, you probably found the “tonic”!

Let’s say it was an E and that you also had several F# in the melody. You probably then have a piece in E minor, a relative key to G major. They both have one sharp (#) in the key signature. In minor, it is often common to alter (change) the 7th note of the scale, in E minor this is D, so you could also see a few D#’s. It is called “harmonic” minor.

What chords suit best to a melody?

The basic chords used for any major or minor scale are only 3.

They are called the Tonic, Subdominant and Dominant, or more commonly; I, IV, and V.

They are like the “primary colors” of music harmony. They can be altered and mixed and matched for more “colors” or harmonies, but you can do just fine with only three too!

How to find them?

The numbers are Latin numerals. They tell us the degree (step) of the scale. Let's say we use the E minor scale again:

E-F#-G-A-B-C-D#-E (called Harmonic Minor)

E = I (tonic), F# = II, G = III, A = IV (subdominant), B = V (dominant), C = VI, D# = VII.

So, the chords (triads) we use are built from E (I), A (IV), and B(V).

We use notes from the scale to build the chords:

  • E-G-B= E minor chord
  • A-C-E= A minor chord
  • B-D#-F#= B major chord

These three chords are the primary chords in E minor.

Now you have to test them with your melody, and where they fit!

Tip: Where the melody has at least some of the notes that matches a chord it will fit best.
Read more about how to fit chords to a melody here.

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