C7 Chord on Ukulele
C7 = C – E – G – A# (Root, Major 3rd, Perfect 5th, Minor 7th)
C7 is arguably even easier to reach than C major: only the A string is fretted, at the first fret instead of the third, with the index finger, while the G, C, and E strings stay open. It's a striking example of how little movement separates a plain major triad from its dominant seventh on this instrument — one string, and only by two frets closer to the nut. Some beginners actually meet C7 before C major, since a few method books introduce it as the even-easier-to-reach shape first.
As the dominant seventh built on C, this chord functions as the V7 in the key of F, giving it a strong pull toward F major whenever a progression needs that resolution. Its sound sits between C major's calm and G7's sharper bite — a milder tension, since its own root note anchors so much of the open-string ring that it doesn't feel as unsettled as some seventh chords do. It's also common in twelve-bar-blues-style ukulele playing, where the tonic chord of a blues progression is very often voiced as a dominant seventh rather than a plain major triad. Because three of its four strings ring completely open, C7 keeps almost all of plain C major's bright, unfretted resonance while adding the seventh's extra color — a rare case on this instrument where a seventh chord loses none of its triad's characteristic openness.
Fingerings
Open Position
How to Practice It
Because it's genuinely a one-finger chord at a very low fret, C7 is a good candidate for practicing fast pivots — try C major to C7 and back, noticing that only the A string's fret number changes (three down to one), which trains the ear to hear how a seventh alters a chord without touching its root, third, or fifth. From there, C7 to F is worth isolating since it's the cadence this chord is built for. Because the fretted note sits so close to the nut, keep the fretting finger's pressure light — over-pressing at the first fret is a common way beginners accidentally pull the pitch sharp on such a short scale length. It's also worth practicing C7 in a slow blues shuffle rhythm rather than a plain strum, since that context is where this particular voicing turns up most often outside a straightforward C7-to-F resolution.
Common Progressions
- V7 – I (C7 – F)
- I – IV – V7 (F – Bb – C7, in the key of F)
- ii – V7 – I (Gm – C7 – F)
- Blues-style turnarounds often treat every chord in a I-IV-V loop as a dominant seventh, C7 included.
FAQ
- What's the difference between C major and C7 on ukulele?
- Only the A string's fret changes — third fret for major, first fret for the dominant seventh — making C7 an even lower, easier reach than the already-simple C major shape.
- What key does C7 resolve into?
- F major — C7 is the V7 chord in the key of F, so it's the natural setup chord right before an F resolution.
- Does C7 show up outside the key of F?
- Yes — it's also common in blues-style playing, where the tonic chord of a progression is often voiced as a dominant seventh from the start rather than a plain major triad.
- Why does C7 use the index finger rather than another finger?
- Using the index finger keeps the middle and ring fingers free to pre-position for whatever comes next, which matters most in a fast-moving progression where C7 is a brief passing chord rather than a place to rest.
- Does C7 lose any of C major's open, ringing sound?
- Barely — three of its four strings stay completely open, the same as plain C major, so C7 keeps nearly all of that chord's bright resonance while adding the seventh's mild tension on the fretted A string alone.
- Where else does this exact one-finger C7 shape get used?
- It's a common building block in ukulele blues shuffles and turnarounds, where a I7-IV7-V7-style progression treats every chord in the cycle as a dominant seventh rather than reserving that color for a single cadence.
- Should a beginner learn C7 before or after C major?
- After is standard practice, since C major establishes the basic strum and open-chord feel first, but the two are close enough in shape that learning C7 shortly afterward reinforces rather than complicates that foundation.
C7 on other instruments: C7 on Guitar, C7 on Piano. Related: how chords are built, chord finder.