Section 1Introduction
A minor seventh is ten semitones — a wide, mildly dissonant interval that is responsible for the bluesy character of dominant 7th chords and the smooth tension of jazz harmony. It wants to resolve, but it does not have to — modern music is full of unresolved minor sevenths used as stable colors.
Section 2How to Find It on the Keyboard
Find any minor seventh in two simple steps. The number tells you the letter. The semitones tell you the accidental.
- Start on any root note. Count 7 letter names (including the root) up the musical alphabet — that gives you the top letter.
- Now count exactly 10 semitones from the root. If the natural top letter is too high or too low, sharpen or flatten it to land on the right pitch.
- Use the explorer above to check yourself in all 12 keys. The two highlighted notes are the m7 from that root.
Quick check: from C, the m7 lands on B♭. From G, it lands on F. From E♭, it lands on D♭.
Section 3Hear It — Song Associations for Ear Training
The fastest way to internalise the minor seventh is to associate it with a tune you already know. Sing the first two notes of any of these and you have the interval.
Section 4The Interval in Chords
Every chord is a stack of intervals. Here is where the minor seventh shows up in common harmony.
| Chord | Name | How m7 Appears |
|---|---|---|
| C7 | Dominant 7th chord | Adds a minor 7th to a major triad — the engine of tonal harmony |
| Cm7 | Minor 7th chord | Adds a minor 7th to a minor triad — smooth, jazzy |
| Cø7 | Half-diminished 7th | Diminished triad + minor 7th — common ii in minor keys |
Section 5Inversion: Flip It Upside Down
When you move the bottom note up an octave (or the top note down an octave), the interval inverts. Two simple rules govern interval inversions:
- Numbers sum to 9. A 2nd inverts to a 7th, a 3rd inverts to a 6th, a 4th inverts to a 5th, and so on (1 + 8 = 9 for unison/octave).
- Quality flips. Major ↔ minor, augmented ↔ diminished, perfect stays perfect.
Section 6Compound Form
A compound interval is the same interval with an extra octave added on top. The character stays the same but the two notes are spread further apart. The compound form of the minor seventh is the Minor Fourteenth (m14) — 22 semitones in total.
Why it matters: chord extensions like 9ths, 11ths, and 13ths are compound intervals stacked above the basic triad. Move it up an octave and you get a wider, more open sound — common in piano voicings and orchestral spacing.
Section 7Enharmonic Equivalents
Two intervals are enharmonic when they sound the same but are spelled differently. Same physical pitches, different musical meaning.
- Augmented Sixth (A6) — ten semitones, e.g. C–A♯ in German augmented sixth chords
On the keyboard, an enharmonic pair sounds identical. On paper, the spelling tells you which scale or chord the note belongs to — and that changes how it functions in the music.
Section 8Frequently Asked Questions
Why does the dominant 7th resolve?
The minor 7th in V7 sits a half step above the 3rd of the I chord, and the 3rd of V7 sits a half step below the root of I. Both notes "lean" toward resolution.
What is the inversion?
A major second. m7 + M2 = 9, minor flips to major.
How does a minor 7th differ from an augmented 6th?
They span the same 10 semitones but are spelled differently. C–B♭ is a minor 7th; C–A♯ is an augmented 6th. The augmented 6th appears in classical chromatic harmony.
Why is the m7 so common in jazz?
It is mild enough to sound stable as a chord color but tense enough to keep harmony moving. Most ii–V–I progressions are entirely built from minor and dominant 7th chords.
How do I find a minor seventh?
Count ten semitones up, or count one whole step down from the octave. C up to B♭; F up to E♭; A up to G.