Music Theory: Keys, Scales and Triads

The table below summarises the basic ideas of music theory that relate to keys, key signatures, scales and triads. The key signature, major triad, minor triad and degrees of the scale are listed for all of the common major keys. Just find the key that you want to look up in the left hand column, then read across to find the triads, key signature etc.

Note that some degrees of the scale (e.g 2nd & 9th) correspond to the same note. The difference is that one (in this case, the 2nd) will be a note within the first octave of the scale, and the other (the 9th) will be in the second octave of the scale.

Thanks to Laramie Sasseville for getting me started with this reference table.

Major Key Key Signature Major Triad Minor Triad 1st 2nd

9th 3rd

10th 4th

11th 5th 6th

13th 7th Octave C C E G C Eb G C D E F G A B C Db b b b b b Db F Ab Db Fb Ab Db Eb F Gb Ab Bb C Db D # # D F# A D F A D E F# G A B C# D Eb b b b Eb G Bb Eb Gb Bb Eb F G Ab Bb C D Eb E # # # # E G# B E G B E F# G# A B C# D# E F b F A C F Ab C F G A Bb C D E F F# # # # # # # F# A# C# F# A C# F# G# A# B C# D# E# F# Gb b b b b b b Gb Bb Db Gb Bbb Db Gb Ab Bb Cb Db Eb F Gb G # G B D G Bb D G A B C D E F# G Ab b b b b Ab C Eb Ab Cb Eb Ab Bb C Db Eb F G Ab A # # # A C# E A C E A B C# D E F# G# A Bb b b Bb D F Bb Db F Bb C D Eb F G A Bb B # # # # # B D# F# B D F# B C# D# E F# G# A# B

Minor keys

To find the notes of the scale for the minor key, look up the scale for the relative major key but start from the root of the minor scale (which will be the 6th of the major scale). In the above example, the scale of B minor is found by reading from the scale of the relative major (D major). Start on the 6th (B), then read across, looping back from the octave to the 2nd.. This gives us B C# D E F# G A as the B minor scale.

Enharmonic equivalents

Also, it might seem a little odd to come across notes such as Fb, for example in a Db minor triad. Although you might be tempted to substitute E instead of Fb, as they are enharmonic equivalents, it is wrong to write a Db minor triad as Db E Ab - you must write the triad as Db Fb Ab.

Other keys

The key signature of the "unusual" key will have seven more sharps or flats than the key with the same letter name. In our example, the key signature for G# major will have seven more sharps than G major. The table lists G major as having one sharp (F#) so G# major will have 8 sharps (F will be double sharp).

The idea of having double sharps or double flats is a little strange when you first come across it, but it's a well established idea in music theory and means you can use consistent rules for scales and keys.

The table below shows the relationships between the major and minor keys. To find the relative major or minor for another key just look up the corresponding entry in the table. For example, to find the relative minor of D major, find D in the major key column - this gives you B minor in minor key column so B minor is the relative minor of D major.

Relative Major Key Relative Minor Key C A minor Db Bb minor D B minor Eb C minor E C# minor F D minor F# D# minor Gb Eb minor G E minor Ab F minor A F# minor Bb G minor B G# minor