Chord & FretC7 · Cavaquinho
Say this out loud: "one, two..." — and stop right there. Uncomfortable, isn't it? The sentence is hanging. That discomfort has a sound: C7 is a sentence without a period. Press play down there.
Listen first
What you just heard
Why does it sound unfinished? Inside C7, two notes are arguing: E and A#. Play the arpeggio again, no rush and catch the second and the last note — the distance between them is the tritone, the tensest interval tonal music knows. C and G keep the house standing while those two argue inside it. And an argument, you know, demands a resolution.
Now it's your hands' turn
On the cavaquinho, four steel strings tuned D–G–B–D pack the chord into a small, bright space — every finger counts. So grab the first position below; the position marked with ⭐ is the easiest to play. Now the experiment that explains this chord better than any explanation: play C7, hold it for one breath, then play F. Felt the door close? Do it again. That relief is the reason this chord exists.
2 more shapes of this chord on the neck
Part of 218,399 voicings and inversions in Chord & Fret Pro — see and play every one.
Precision Tuner — Before you play these shapes, get in tune — chromatic tuner and reference tones · see it in Chord & Fret
The other positions earn their keep in blues and jazz, where this chord is practically the official language; learn them one at a time.
Left-handed? Mirror's right here
What is C7?
C7: C Major with Seventh. The notes are C, E, G, Bb (fixed-do: Do, Mi, Sol, Si♭) — the degrees 1–3–5–b7.
Where this chord lives
Its job is fixed: C7 is a dominant, and dominants live as VII7 in D minor, V7 in F major. Plainly: where it enters, the song is about to leave the room. A chart full of 7th chords is a song that won't sit still.
Transpose & Capo — Need it in another key? Move the whole chart and find the easiest capo · try it in Chord & Fret
Identify Chord — Found a shape on your own fretboard? The app names it back · use it in Chord & Fret
Where it tends to go
Treating C7 as the home chord (I) of its key, it tends to go toward the pre-dominant (Dm / F) or the dominant (G / B°) — and the dominant pulls back home. It's a tendency, not a law.
Every shape of C7 lives in Chord & Fret Pro — 4 instruments, 16 tunings, 41 chord types and 57 scales, in every key. Start free. Unlock everything with Pro. Plays offline. Made by musicians, no ads.
When you want to go further
For soloing, C Mixolydian (C D E F G A Bb · 1 2 3 4 5 6 b7: the major scale with a lowered seventh — the blues accent); C Lydian dominant (C D E F# G A Bb · 1 2 3 #4 5 6 b7: a mixolydian with a raised fourth: the dominant in formalwear) cover the whole chord. And look at the first swap on the list below: that's the famous tritone substitution, the twin dominant living three whole steps from here, the one arrangers reach for when they want to arrive at the same place by a prettier road.
C Mixolydian
4 more scale positions on the neck
Chord & Fret Pro maps 35,178 mapped scale shapes — hear and play them all.
The same C Mixolydian in its main shapes along the neck — pick whichever position sits under your hand. The rings mark the guide notes (the 3rd and 7th) that carry this chord's color.
Scale — The whole scale on the neck — in boxes or three notes per string, with an exercise and a tempo ramp · try it in Chord & Fret
Improvising in context
To improvise over C7 as home, the C Mixolydian scale covers it whole — it contains every note of the chord. And when the dominant (G) pulls back, the leading tone B is the note that wants to resolve home.
Swaps that work:
- Gb7Gb7Gb7Gb7 — Tritone substitution (shared 3rd–7th tritone)
- Gm7Gm7Gm7Gm7 — Forms a II–V: precede with this ii
- Dbdim7 — Passing diminished (ascending)
Reharmonize — Want richer substitutions? Reharmonize the progression in a tap · open in Chord & Fret
You already know how this sentence ends. The period after C7 is called F — go there and close it with your own fingers.