Minor 7th #5
m7#5
0 - 3 - 8 - 10Minor + augmented 5th + minor 7th
About Minor 7th #5
A minor seventh sharp five chord is a minor seventh whose fifth has been raised a semitone — in C that is C, E♭, G♯ and B♭, written Cm7♯5. It is rare as a chord symbol and common as a sound, because the same four notes spell an add9 chord a major third below, and that is usually how players arrive at it.
Notes and formula
The formula is 1 – ♭3 – ♯5 – ♭7, or 0 – 3 – 8 – 10 in semitones. A minor triad with an augmented fifth, plus a minor seventh.
The raised fifth is what makes the chord unusual: a minor third and an augmented fifth are six semitones apart, so the chord contains a tritone in a place where minor chords normally have none.
The chord it shares its notes with
Rearranged from A♭, the notes are A♭–B♭–C–E♭ — an A♭ major triad with a ninth added, written A♭add9. The identity is exact, and it explains why the chord sounds far less strange than its symbol suggests.
Which name applies is decided by the bass, as always. Over a C the chord reads as a minor seventh with an alteration; over an A♭ it reads as an ordinary bright add9 that any folk guitarist would recognise.
How to play it
On piano the plain form is C–E♭–G♯–B♭. Most players voice it as A♭–C–E♭–B♭ over a C in the bass, which is the same chord and considerably easier to hear.
On guitar the movable form is x3142x, sounding C–E♭–B♭–G♯. It is awkward, and the add9 shape at the third fret is the usual route to the same sound.
Where it appears
Almost always as a passing sonority rather than a chosen chord: a minor seventh whose fifth is rising toward the sixth passes through it, and the symbol is written after the fact by whoever transcribed the part.
It also appears in modal jazz where the harmony is built from stacked intervals rather than from a key, and the symbol is the least misleading way to name what the players are holding.
Minor seventh sharp five or half-diminished
The two are opposites and are confused constantly because both alter the fifth of a minor seventh. Cm7♯5 raises it to G♯; Cm7♭5 lowers it to G♭.
They behave differently as well. The half-diminished belongs to minor keys and rests; this chord belongs to no key in particular and moves.
Scales that contain it
The third mode of melodic minor contains the chord, and so does the natural minor scale a major third below — which is the same statement made from the add9 side.
In practice players think in terms of the underlying add9: play A♭ major pentatonic over a Cm7♯5 and every note lands, which is faster than reasoning about modes of the written root.
Frequently asked questions
What notes are in a Cm7♯5 chord?
C, E♭, G♯ and B♭. The same four notes spell A♭add9, which is how most players find the shape.
Is m7♯5 a real chord or a transcription artefact?
Both, in practice. It occurs genuinely in modal writing, and it also appears in charts where a rising inner voice happened to be caught by whoever wrote the symbol.
What is the difference between m7♯5 and m7♭5?
The direction of the alteration. Sharp five raises the fifth to G♯ and produces an add9 chord in disguise; flat five lowers it to G♭ and produces the half-diminished chord of minor-key jazz.