The C7#5 guitar chord is a 7th sharp 5th chord with the notes C, E, G#, A#. Its first guitar voicing is a barre chord at fret 1: low E string open; A string at fret 1 (index finger); D string at fret 2 (middle finger); G string at fret 1 (index finger); B string at fret 1 (index finger); high e string open. Whether you are learning it for the first time or checking a voicing, this page has the notes, the guitar fingerings, the inversions and alternatives, and the progressions it appears in.
What notes are in the C7#5 chord?
The C7#5 chord is a 7th sharp 5th chord, and its notes are fixed: C, E, G#, A#. Every voicing on every instrument uses these same notes, in some order and in some octave — change one of them and you are playing a different chord. The table below lists each note with its interval from the root C, so you can see the structure of C7#5 at a glance. On the guitar, the barre chord voicing is the place to hear it in C7#5.
| Note | Interval |
|---|---|
| C | Root |
| E | 3 |
| G# | #5 |
| A# | b7 |
The root is C, the note the chord is named after and the note your ear hears as home. Above it, the intervals in C7#5 are 3, #5, b7. Those intervals are the fingerprint of the 7th sharp 5th quality — any chord with the same interval pattern, on any root, is the same kind of chord. On the guitar, the notes appear in the order the fingering dictates, but the set of notes never changes.
C7#5 sounds sharp and colourful, a dominant chord that refuses to sound ordinary. Listen for that character when you play it — if C7#5 does not sound that way, one of the notes is probably wrong, and the table above is the place to check. On the guitar, the barre chord of C7#5 puts those notes under your fingers in the order the fingering lists them.
Comparing C7#5 with its closest relatives helps to fix it in your ear. In short, 7#5 against dominant 7th: C7#5 raises the 5th to G# where the plain dominant 7th keeps the perfect 5th G. The raised 5th adds lift and tension at the same time. Practise the two chords back to back and listen to the one note that changes — that single note is the difference between the two chords. On the guitar, the barre chord voicing is the place to hear it in C7#5.
How to play C7#5 on guitar
On the guitar, C7#5 has 3 voicings in the data below, and each one uses the same notes — C, E, G#, A# — in a different place on the neck. The first voicing below is the one to learn first, and the alternatives cover the rest of the neck. Finger numbers below use 1 for the index finger, 2 for the middle finger, 3 for the ring finger and 4 for the little finger, and x means the string is not played.
The barre chord is the voicing to learn if you want C7#5 in open position: low E string open; A string at fret 1 (index finger); D string at fret 2 (middle finger); G string at fret 1 (index finger); B string at fret 1 (index finger); high e string open. It barres across strings 4 to 5 at fret 1 with the index finger. The barre is the hard part: the index finger must press every string from 4 to 5 evenly at fret 1, so roll it slightly onto its bony side and keep it close to the fret wire. If the barre buzzes, move it a fraction closer to the fret and press from the arm, not the thumb alone. Strum or pluck it slowly first and check that every note in C7#5 — C, E, G#, A# — sounds, with no buzz and no accidental open string.
Another way to play C7#5 is the movable voicing, in around fret 2: low E string muted; A string at fret 3 (middle finger); D string at fret 2 (index finger); G string at fret 3 (ring finger); B string at fret 5 (little finger); high e string at fret 4 (little finger). The challenge here is the muted string: 1 string is marked x, and it needs to stay silent. Let the edge of a fretting finger rest lightly on it — muting by touch, not by pressing. Strum or pluck it slowly first and check that every note in C7#5 — C, E, G#, A# — sounds, with no buzz and no accidental open string.
For the open position, C7#5 sits in open position: low E string muted; A string at fret 3 (ring finger); D string at fret 2 (middle finger); G string at fret 3 (little finger); B string at fret 1 (index finger); high e string at fret 4 (little finger). The challenge here is the muted string: 1 string is marked x, and it needs to stay silent. Let the edge of a fretting finger rest lightly on it — muting by touch, not by pressing. Strum or pluck it slowly first and check that every note in C7#5 — C, E, G#, A# — sounds, with no buzz and no accidental open string.
Choosing between the voicings of C7#5 is a musical decision, not a right-or-wrong one. The open or low-position voicing rings the most and suits strumming, while a barre or movable voicing lets you slide C7#5 up the neck to any key without changing the shape. When you change chords, pick the voicing of C7#5 that sits closest to the chord before it — shorter moves between shapes mean faster, cleaner changes. Practise the change into C7#5 from the chord that comes before it in your song, not the chord on its own, because the move is the skill. On the guitar, the barre chord of C7#5 puts those notes under your fingers in the order the fingering lists them.
A short practice routine for C7#5 on the guitar: play the first voicing four times slowly, checking each note, then change to it from the chord a fourth above C and back, four times, at a slow tempo. Then play the second voicing the same way. If a note buzzes, stop and fix the finger placement rather than playing through the buzz — clean notes at a slow tempo become clean notes at full tempo, while buzzes practised fast become habits. Use the Guitar Chord Finder to see the diagram for C7#5 while you practise, and the Chord Finder to compare it with the same chord on other instruments.
Common mistakes
These are the mistakes that most often make C7#5 sound wrong on the guitar, and each one has a concrete fix. Work through them one at a time rather than trying to fix everything at once.
Playing a perfect 5th. If the 5th is G the chord is a plain dominant 7th. The sharpened 5th G# is the note that makes it altered. On the guitar, start with the first voicing above and listen for the notes C, E, G#, A# in C7#5.
Confusing it with the augmented triad. The augmented triad has no 7th. C7#5 adds the flattened 7th A# to the augmented triad — that 7th is essential. On the guitar, start with the first voicing above and listen for the notes C, E, G#, A# in C7#5.
Using it as a tonic. C7#5 is an altered dominant. It wants to resolve to the tonic a fourth above its root. On the guitar, start with the first voicing above and listen for the notes C, E, G#, A# in C7#5.
Voicing it too low. G# low down can sound muddy. Keep the sharpened 5th in a higher octave than the root. On the guitar, start with the first voicing above and listen for the notes C, E, G#, A# in C7#5.
Where C7#5 is used
C7#5 is not a diatonic triad in any major or minor key, because it is an extended or altered chord, but its base triad belongs to the key of C major, the key of F major, the key of G major. a passing dominant in chromatic progressions. As a dominant-type chord it also points toward F major, the key a perfect fourth above C, which is the tonic it most often resolves to. That is where C7#5 does its work: not as a home chord, but as a chord that creates movement and then resolves. On the guitar, the barre chord of C7#5 puts those notes under your fingers in the order the fingering lists them.
Because C7#5 is an extended or altered chord, it appears in progressions as a colour or a dominant rather than as a diatonic staple. Try it in place of the plain C triad in a progression you already know, and listen to how the extra notes change the feel — that substitution is the usual way extended chords enter real music. The Chord Progression Builder lets you try C7#5 in a progression in any key and hear how it connects to the chords around it. On the guitar, the barre chord voicing is the place to hear it in C7#5.
The same chord on other instruments is covered in C7#5 on piano, C7#5 on ukulele, C7#5 on bass, and the scales that fit over it are the C major scale and the C minor pentatonic scale. Learning C7#5 on the guitar and then checking it on another instrument is one of the best ways to fix the notes — C, E, G#, A# — in your memory, because the notes stay the same while everything else changes.
Practising C7#5
A short worked example makes C7#5 concrete. Play the four-chord progression F – C – Dm – A# in F major, the key C7#5 most often resolves toward: F – C – Dm – A#. Play each chord for one bar at a slow tempo, and listen to how C7#5 sounds in that sequence — whether it feels like home, like a lift, or like a chord on its way somewhere else. Then play the same four chords in a different order, starting on C7#5 itself, and notice how its character changes when it opens the progression instead of sitting inside it. On the guitar, the barre chord of C7#5 puts those notes under your fingers in the order the fingering lists them.
For a second exercise, play C7#5 and then the chord a fourth above C, back and forth, four times each. That move — a chord and the chord a fourth above it — is the most common resolution in Western music, and it is the move C7#5 is built for when it acts as a dominant. Finish by playing C7#5 on its own, slowly, and naming each note out loud as you play it: C, E, G#, A#. Naming the notes while you play them is what turns a shape into knowledge you can use in any key. Test yourself with the Practice Chord Quiz and keep time with the Metronome as the tempo rises. On the guitar, start with the first voicing above and listen for the notes C, E, G#, A# in C7#5.
Frequently asked questions
How do you play C7#5 on the guitar?
The first voicing is the barre chord: frets 0–1–2–1–1–0, fingers 0–1–2–1–1–0, on the guitar. That voicing uses the notes C, E, G#, A#, and it is the one to learn first. The page above lists more voicings for C7#5, so you can choose the shape nearest the chords around it.
Is C7#5 hard to play on the guitar?
It depends on the voicing. The first voicing of C7#5 on the guitar is the easiest starting point, and the movable voicings further up the neck are harder because they need a barre or a wider stretch. Practise the first voicing cleanly at a slow tempo before you try the others, and the harder shapes will come more easily.
What is the easiest voicing of C7#5 on the guitar?
The barre chord is the easiest voicing listed for C7#5 on the guitar: frets 0–1–2–1–1–0, fingers 0–1–2–1–1–0. Learn that shape first, get every note ringing cleanly, and only then move on to the alternative voicings further up the neck.
What notes are in C7#5?
C7#5 contains C, E, G#, A#: root C, major 3rd E, sharpened 5th G# and flattened 7th A#. The sharpened 5th is the note that makes it an altered dominant. On the guitar, the voicings above put that note under your fingers.
What is the difference between C7#5 and C7?
C7 has the perfect 5th G; C7#5 raises it to G#. C7#5 sounds tenser and more exotic, and it is used as an altered dominant in jazz. On the guitar, the voicings above put that note under your fingers.