The minor 7th and major 7th differ by one semitone: a minor 7th spans ten semitones and a major 7th spans eleven. C to Bb is a minor 7th and C to B is a major 7th, and that single semitone decides whether a chord is a dominant 7th or a major 7th.
What is the difference between a minor 7th and a major 7th?
The minor 7th and the major 7th are the two largest intervals within an octave, and they differ by exactly one semitone. A minor 7th spans ten semitones and a major 7th spans eleven, one semitone below the octave. C to Bb is a minor 7th, ten semitones, while C to B is a major 7th, eleven semitones. Both intervals span seven letter names, which is why both are 7ths, and the semitone count is what decides the quality. The two 7ths sound very different, and they play opposite roles in harmony. The major 7th sounds smooth, dreamy and slightly tense, because it sits a semitone below the octave and leans toward it, which is why major 7th chords sound so settled and luminous. The minor 7th sounds bluesy, relaxed and open, because it sits a whole tone below the octave, which is why dominant 7th chords sound restless and ready to move. That one semitone is the difference between a chord that stays and a chord that goes.
How the two 7ths compare
Count them the same way as any interval: letters first, then semitones. G to F is seven letters, G, A, B, C, D, E, F, and ten semitones, so it is a minor 7th. G to F# is seven letters and eleven semitones, so it is a major 7th. D to C is a minor 7th, ten semitones, while D to C# is a major 7th, eleven semitones. The pattern holds on every root: the minor 7th is always the note ten semitones above the root, and the major 7th is always the note eleven semitones above it, which is the 7th degree of the major scale. The 7ths decide the type of every 7th chord. A dominant 7th chord has a minor 7th, a major 7th chord has a major 7th, and a minor 7th chord has a minor 7th on a minor triad. The 7th is also the note that decides whether a scale is major or minor: a major scale has a major 7th above its root, a natural minor scale has a minor 7th, and the harmonic minor scale raises the 7th back to major. The G7 guitar chord and the Gmaj7 guitar chord show the two 7ths deciding the chord type, and the interval calculator measures either 7th from any root.
Worked example — 7ths above A. A to G is seven letters, A, B, C#, D, E, F#, G, and ten semitones, so it is a minor 7th, and A7 is A, C#, E and G. A to G# is seven letters and eleven semitones, so it is a major 7th, and Amaj7 is A, C#, E and G#. Play A7 and listen for the restless, bluesy sound of the minor 7th, then play Amaj7 and listen for the smooth, dreamy sound of the major 7th. The A7 guitar chord and the Amaj7 guitar chord show the two shapes, and the A major scale shows the major 7th, G#, as its 7th degree.
How to practise hearing the 7ths
Practise the 7ths as a pair, minor then major, on the same root, so your ear learns the difference between the bluesy minor 7th and the dreamy major 7th.
- Play C and Bb together, a minor 7th, then C and B together, a major 7th, and listen for the minor 7th sounding relaxed and the major 7th sounding tense.
- Sing a minor 7th above a root note, then raise the top note by a semitone to sing the major 7th, checking yourself against the piano.
- Play the G7 guitar chord and the Gmaj7 guitar chord back to back, and notice that only the top note changes.
- Find the 7th in every chord of the key of C major, and name whether each one is major or minor before you check.
- Use the interval calculator to quiz yourself on 7ths from random roots until you can name the quality from the sound alone.
Common mistakes
- Calling the minor 7th a flat 7th and stopping there — The minor 7th is often called the flat 7th, but the name is only a shortcut: the interval is a minor 7th, ten semitones, and calling it flat does not explain why it behaves the way it does in chords.
- Thinking the major 7th is always dissonant — The major 7th is a dissonance on its own, because it sits a semitone below the octave, but inside a major 7th chord it sounds smooth and settled, because the chord frames it as a colour rather than a clash.
- Confusing the 7th with the octave — A major 7th is one semitone below the octave, and the two are easy to confuse by ear. If the top note sounds almost like the octave but slightly flat, it is the major 7th, and if it sounds like the same note higher up, it is the octave.
Quick reference
This table lists the minor and major 7ths above six roots, so you can see the one-semitone difference working on the roots you will meet most often. In every row the minor 7th is the note ten semitones above the root and the major 7th is the note eleven semitones above it, and the letter count is seven in both columns.
| Root | Minor 7th (10 semitones) | Major 7th (11 semitones) |
|---|---|---|
| C | A# | B |
| G | F | F# |
| D | C | C# |
| A | G | G# |
| E | D | D# |
| F | D# | E |
Play each row on piano as a pair, minor 7th first and major 7th second, and listen for the relaxed bluesy sound giving way to the tense dreamy sound as the top note rises by one semitone. When the pairs feel familiar, build the dominant 7th and major 7th chords on each root, and notice that the 7th is the only note that changes between the two.
Frequently asked questions
What is a minor 7th?
A minor 7th is an interval of ten semitones between two notes seven letters apart, such as C to Bb or G to F. It is the 7th of a dominant 7th chord, and it sounds bluesy and relaxed.
What is a major 7th?
A major 7th is an interval of eleven semitones between two notes seven letters apart, such as C to B or G to F#. It is the 7th of a major 7th chord, and it sounds smooth, dreamy and slightly tense.
How do I tell a minor 7th from a major 7th?
Count the semitones: ten is minor and eleven is major. By ear, the minor 7th sounds a whole tone below the octave, relaxed and open, while the major 7th sounds a semitone below the octave, tense and leaning upward.
Why is the 7th so important in chords?
Because the 7th decides the type of every 7th chord: a minor 7th makes a dominant 7th chord, a major 7th makes a major 7th chord, and the 7th is the note that creates the tritone in a dominant 7th chord, which drives the resolution.
Do 7ths appear in scales?
Yes. A major scale has a major 7th above its root, a natural minor scale has a minor 7th, and the harmonic minor scale raises the 7th to major. The 7th is the note that gives a scale its leading-note pull toward the tonic.