What notes are in the C7b5 chord?

C7b5 is made of C, E, Gb and Bb — the 1, 3, b5 and b7 degrees of a seventh flat five chord built on C.

What keys use the C7b5 chord?

No major or natural-minor key contains all 4 notes of C7b5. Chords like this arrive as borrowed harmony — secondary dominants, harmonic-minor colour, or chromatic passing chords — rather than as one of a key's native chords.

How do you play C7b5 on guitar and piano?

This page shows C7b5 on guitar and piano — 5 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.

Chord · C Dominant 7♭5

C7♭5 Chord

C7♭5 is C, E, Gb and Bb — tritone-substitution flavor; whole-tone sound.

Hear it

C7♭5 on every instrument

The same 4 notes, 2 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.

Guitar2 voicings

Piano3 voicings

What C7♭5 is made of

C7b5 (C seventh flat five) is built from the notes C, E, Gb, Bb, with the interval pattern 1, 3, b5, b7.

Stack 1, 3, b5 and b7 on a root of C and you get C, E, Gb and Bb. That interval recipe is what makes the chord a seventh flat five chord — move the same shape to another root and the character travels with it, which is why D7♭5 sounds like a transposed C7♭5.

Dominant 7♭5: Tritone-substitution flavor; whole-tone sound.

Spelling: the notes above are written the way a score would write them, not simplified to the nearest piano key. That is why this chord is spelled with G♭ rather than its enharmonic equivalent.

Keys that contain C7♭5

No major or natural-minor key contains all 4 of these notes — this one gets borrowed.

Chords like this one sit outside the diatonic set — they arrive as secondary dominants, borrowed chords or passing harmony. Browse every key to see which progressions pull it in.

Other chords on C

Same root, different colour.

CC Major CmC Minor CdimC Diminished CaugC Augmented Csus2C Suspended 2nd Csus4C Suspended 4th C5C Power Chord C6C Major 6th

The same seventh flat five shape, moved

The identical interval recipe, built on other roots.

D7♭5D Dominant 7♭5 E7♭5E Dominant 7♭5 F7♭5F Dominant 7♭5 G7♭5G Dominant 7♭5 A7♭5A Dominant 7♭5 B7♭5B Dominant 7♭5 F♯7♭5F# Dominant 7♭5 D♭7♭5Db Dominant 7♭5

Questions people ask about C7b5

What notes are in the C7b5 chord?: C7b5 is made of C, E, Gb and Bb — the 1, 3, b5 and b7 degrees of a seventh flat five chord built on C.
What keys use the C7b5 chord?: No major or natural-minor key contains all 4 notes of C7b5. Chords like this arrive as borrowed harmony — secondary dominants, harmonic-minor colour, or chromatic passing chords — rather than as one of a key's native chords.
How do you play C7b5 on guitar and piano?: This page shows C7b5 on guitar and piano — 5 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.

Learn the theory behind it

Why C7♭5 behaves the way it does — the guides that explain the chord instead of just spelling it.

Functional Harmony: Three Roles, One EngineDiminished chords are almost always doing a job. This explains which one.6 min read Cadences — The Four Ways a Phrase EndsWhere all that tension goes — how the chord resolves into the next one.4 min read Voice Leading — Hold What You Can, Move Only What You MustHalf-steps do the work here. Voice leading is how you find them.6 min read