Major and minor keys differ in their scales and their chords: a major key is built from the major scale, with a major tonic chord, while a minor key is built from the natural minor scale, with a minor tonic chord. C major has the chords C, Dm, Em, F, G, Am and Bdim, while A minor has Am, Bdim, C, Dm, Em, F and G.
What is the difference between major and minor keys?
Major and minor keys differ in their scales, their chords and their sound. A major key is built from the major scale, which has a major 3rd, a major 6th and a major 7th above its root, and its tonic chord is major. A minor key is built from the natural minor scale, which has a minor 3rd, a minor 6th and a minor 7th above its root, and its tonic chord is minor. C major is built from C, D, E, F, G, A, B, while A minor is built from A, B, C, D, E, F, G, and the two scales share the same notes but start from different roots. The sound differs because the tonic chord differs. A major key sounds bright and settled, because its home chord is major, with a major 3rd that sounds cheerful. A minor key sounds dark and sad, because its home chord is minor, with a minor 3rd that sounds sombre. The chords of the key differ too: a major key has three major chords, three minor chords and one diminished chord, while a minor key has three minor chords, three major chords and one diminished chord, in a different order, so the harmonic landscape of the two keys is a mirror image.
How major and minor keys compare
Compare the diatonic chords of C major and A minor, which are relative keys sharing the same notes, and the comparison is clear. C major has C, Dm, Em, F, G, Am and Bdim, in the order I, ii, iii, IV, V, vi, vii. A minor has Am, Bdim, C, Dm, Em, F and G, in the order i, ii, iii, iv, v, VI, VII. The chords are identical, but their functions are different: C is the tonic in C major and the III chord in A minor, while Am is the vi chord in C major and the tonic in A minor. The same seven chords, heard from two different homes, produce two different keys. The minor key also has a harmonic variant that the major key does not have: the harmonic minor scale raises the 7th degree, which turns the v chord from minor to major and gives the minor key a strong dominant. In A minor the v chord is Em, E, G and B, but the V chord is E major, E, G# and B, where the G# comes from the harmonic minor scale. That major V chord is what gives minor-key music its pull back to the tonic, and it is the reason minor keys use two scales, natural minor for melodies and harmonic minor for harmony, while major keys use one. The key of C major and the key of A minor show the two keys side by side.
Worked example — G major vs E minor. G major is built from G, A, B, C, D, E, F#, and its chords are G, Am, Bm, C, D, Em and F#dim. E minor is built from E, F#, G, A, B, C, D, and its chords are Em, F#dim, G, Am, Bm, C and D. The chords are identical, but the tonic is different: G in the major key, E in the minor key. Play the I–V–vi–IV progression in G major, G, D, Em, C, and then play the i–VI–III–VII progression in E minor, Em, C, G, D, and listen for the same chords sounding major in one place and minor in the other. The key of G major and the key of E minor show the pair.
How to practise major and minor keys
Practise major and minor keys as pairs, relative major then relative minor, so your ear learns to hear the same notes from two different homes.
- Play the chords of the key of C major in order, then the chords of the key of A minor, and listen for the same seven chords in a different order.
- Play a major scale and then the natural minor scale on the same root, back to back, and listen for the 3rd, 6th and 7th dropping by a semitone.
- Find the relative minor of the key of D major and the key of F major, and check that each pair shares the same key signature.
- Play the I–V–vi–IV progression in C major and then the i–VI–III–VII progression in A minor, and compare the feeling of the two.
- Use the relative major minor finder to find the relative of any key, and check your answer by counting down a minor 3rd.
Common mistakes
- Thinking a minor key is just a sad major key — A minor key has its own scale, its own chords and its own harmonic rules, including the harmonic minor scale and the major V chord. Treating it as a sad version of the major key misses the structure that makes it work.
- Using the natural minor V chord — The natural minor scale gives a minor v chord, which does not pull home. Minor-key music uses the harmonic minor scale for the V chord, making it major, and that major V chord is what drives the cadence.
- Confusing relative and parallel keys — C major and A minor are relative, sharing the same notes, while C major and C minor are parallel, sharing the same root. The two relationships are different, and confusing them leads to wrong chord choices.
Quick reference
This table compares the diatonic chords of C major and A minor, which are relative keys sharing the same seven notes, so you can see that the chords are identical and only their functions differ. In C major the tonic is C and the vi chord is Am, while in A minor the tonic is Am and the III chord is C, and the same seven chords serve two different homes.
| Degree | C major chord | A minor chord |
|---|---|---|
| I / i | C major | A minor |
| ii / ii° | D minor | B diminished |
| iii / III | E minor | C major |
| IV / iv | F major | D minor |
| V / v | G major | E minor |
| vi / VI | A minor | F major |
| vii° / VII | B diminished | G major |
Work through the table by playing each row on your instrument, first as the C major chord and then as the A minor chord, and listening for the same chord sounding like a tonic in one place and like a passing chord in the other. When you can hear the difference, you understand the relationship between major and minor keys.
Frequently asked questions
What is the difference between a major key and a minor key?
A major key is built from the major scale, with a major tonic chord, while a minor key is built from the natural minor scale, with a minor tonic chord. C major has the chords C, Dm, Em, F, G, Am and Bdim, while A minor has Am, Bdim, C, Dm, Em, F and G.
Do major and minor keys share the same notes?
Relative major and minor keys do: C major and A minor share the notes C, D, E, F, G, A, B. Parallel major and minor keys do not: C major and C minor share only the root, C, and their other notes differ.
Why does a minor key sound sad?
Because its tonic chord is minor, with a minor 3rd that sounds dark and sombre, and because its scale has a minor 3rd, 6th and 7th. The association is partly cultural and partly acoustic, but it is consistent enough that composers have relied on it for centuries.
Can a song change from major to minor?
Yes, and many do. Moving from a major key to its relative minor, or to its parallel minor, is a common way to change the mood of a song, and the modulation is smooth because the keys share notes or a root.
Which is more common, major or minor keys?
Major keys are more common in pop and folk music, while minor keys are more common in rock, metal and classical music. Both appear constantly, and the choice depends on the mood the composer wants.