C#7b5 on the guitar is a 7th flat 5th chord made from C#, F, G, B. Its first guitar voicing is the open position: low E string muted; A string at fret 4 (ring finger); D string at fret 3 (middle finger); G string open; B string open; high e string at fret 1 (index finger). Below you will find its notes and intervals, every usable voicing on the guitar, the common mistakes players make with it and the keys and progressions where it belongs.
What notes are in the C#7b5 chord?
The C#7b5 chord is a 7th flat 5th chord, and its notes are fixed: C#, F, G, B. 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 C#7b5 at a glance. On the guitar, the open position of C#7b5 puts those notes under your fingers in the order the fingering lists them.
| Note | Interval |
|---|---|
| C# | Root |
| F | 3 |
| G | b5 |
| B | 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 C#7b5 are 3, b5, b7. Those intervals are the fingerprint of the 7th flat 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.
C#7b5 sounds sharp and unresolved, a V chord that pulls to the tonic with extra tension. Listen for that character when you play it — if C#7b5 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 open position of C#7b5 puts those notes under your fingers in the order the fingering lists them.
Comparing C#7b5 with its closest relatives helps to fix it in your ear. In short, 7b5 against dominant 7th: C#7b5 flattens the 5th to G where the plain dominant 7th keeps the perfect 5th G#. That one change adds a whole new layer of tension. Play both chords slowly, one after the other, and notice which note moves. Naming that note out loud while you play is the fastest way to learn the difference. On the guitar, the open position voicing is the place to hear it in C#7b5.
How to play C#7b5 on guitar
On the guitar, C#7b5 has 3 voicings in the data below, and each one uses the same notes — C#, F, G, B — in a different place on the neck. There are 3 voicings listed for C#7b5 on the guitar; learn the first, then add the others as you need them. 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 open position puts C#7b5 in open position: low E string muted; A string at fret 4 (ring finger); D string at fret 3 (middle finger); G string open; B string open; high e string at fret 1 (index 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 C#7b5 — C#, F, G, B — sounds, with no buzz and no accidental open string.
For the barre chord, C#7b5 sits in around fret 3: low E string at fret 3 (index finger); A string at fret 4 (middle finger); D string at fret 3 (index finger); G string at fret 4 (ring finger); B string at fret 6 (little finger); high e string at fret 3 (index finger). It barres across strings 1 to 6 at fret 3 with the index finger. The barre is the hard part: the index finger must press every string from 1 to 6 evenly at fret 3, 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 C#7b5 — C#, F, G, B — sounds, with no buzz and no accidental open string.
Another way to play C#7b5 is the movable voicing, in around fret 3: low E string muted; A string at fret 4 (ring finger); D string at fret 3 (index finger); G string open; B string open; high e string at fret 3 (middle 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 C#7b5 — C#, F, G, B — sounds, with no buzz and no accidental open string.
Choosing between the voicings of C#7b5 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 C#7b5 up the neck to any key without changing the shape. When you change chords, pick the voicing of C#7b5 that sits closest to the chord before it — shorter moves between shapes mean faster, cleaner changes. Practise the change into C#7b5 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, start with the first voicing above and listen for the notes C#, F, G, B in C#7b5.
A short practice routine for C#7b5 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 C#7b5 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 C#7b5 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.
Voicing it too low. The flattened 5th low down can sound muddy against the root. Keep G in a higher octave. On the guitar, the open position of C#7b5 puts those notes under your fingers in the order the fingering lists them.
Overusing altered dominants. A run of altered chords loses its effect. Use C#7b5 where the tension earns its place — before a resolution. On the guitar, the open position voicing is the place to hear it in C#7b5.
Barre collapsing on the high strings. In a barre voicing of C#7b5, the high strings are the ones that buzz first, because the index finger presses hardest near the thumb. If the top notes of C#7b5 sound dead, roll the barring finger slightly toward the fret and press from the arm, not from squeezing the neck. On the guitar, start with the first voicing above and listen for the notes C#, F, G, B in C#7b5.
Playing a perfect 5th. If the 5th is G# the chord is a plain dominant 7th. The flattened 5th G is the note that makes it altered. On the guitar, start with the first voicing above and listen for the notes C#, F, G, B in C#7b5.
Where C#7b5 is used
C#7b5 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 C#7b5 does its work: not as a home chord, but as a chord that creates movement and then resolves. On the guitar, the open position of C#7b5 puts those notes under your fingers in the order the fingering lists them.
Because C#7b5 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 C#7b5 in a progression in any key and hear how it connects to the chords around it. On the guitar, the open position voicing is the place to hear it in C#7b5.
The same chord on other instruments is covered in C#7b5 on piano, C#7b5 on ukulele, C#7b5 on bass, and the scales that fit over it are the C# major scale and the C# minor pentatonic scale. Learning C#7b5 on the guitar and then checking it on another instrument is one of the best ways to fix the notes — C#, F, G, B — in your memory, because the notes stay the same while everything else changes.
Practising C#7b5
A short worked example makes C#7b5 concrete. Play the four-chord progression F# – C# – D#m – B in F# major, the key C#7b5 most often resolves toward: F# – C# – D#m – B. Play each chord for one bar at a slow tempo, and listen to how C#7b5 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 C#7b5 itself, and notice how its character changes when it opens the progression instead of sitting inside it. On the guitar, the open position of C#7b5 puts those notes under your fingers in the order the fingering lists them.
For a second exercise, play C#7b5 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 C#7b5 is built for when it acts as a dominant. Finish by playing C#7b5 on its own, slowly, and naming each note out loud as you play it: C#, F, G, B. 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#, F, G, B in C#7b5.
Frequently asked questions
Is C#7b5 hard to play on the guitar?
It depends on the voicing. The first voicing of C#7b5 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 C#7b5 on the guitar?
The open position is the easiest voicing listed for C#7b5 on the guitar: frets x–4–3–0–0–1, fingers 0–3–2–0–0–1. 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 C#7b5?
C#7b5 contains C#, F, G, B: root C#, major 3rd F, flattened 5th G and flattened 7th B. The flattened 5th is the note that makes it an altered dominant. On the guitar, check the first voicing above for that note.
What is the difference between C#7b5 and C#7?
C#7 has the perfect 5th G#; C#7b5 flattens it to G. C#7b5 sounds tenser and more chromatic, and it is used as an altered dominant in jazz. On the guitar, check the first voicing above for that note.
Where is C#7b5 used?
C#7b5 is an altered V chord in jazz, used before a resolution to the tonic, and as a tritone substitute for the dominant a tritone away. On the guitar, check the first voicing above for that note.