Ukulele tuner – Slack Key (GCEG)
G-C-E-G · Open
Press “Start tuner” – the browser will ask for microphone access. Sound is analysed on this device and never uploaded.
This free online tuner listens through your microphone and shows how close each string of your Ukulele is to Slack Key (GCEG) tuning (G-C-E-G). Play a string, watch the needle, and turn the peg until the meter glows green. If you prefer tuning by ear, tap any string card to hear its reference tone.
About Slack Key (GCEG) tuning
Compared with Standard (GCEA), Slack Key (GCEG) moves 1 string. Every change is downward, the largest by 2 semitones, so the instrument sits at lower tension than in Standard (GCEA).3 strings stay exactly where they were.
| String | Standard (GCEA) | Slack Key (GCEG) | Change |
|---|---|---|---|
| 4 | A4 | G4 | down 2 semitones |
Played open, the strings sound G-C-E-G – from C4 at the bottom to G4 at the top, a span of 7 semitones.
Slack Key (GCEG) is re-entrant: the strings do not rise steadily in pitch, so the string nearest your thumb is not the lowest note available. That is deliberate, and it is a large part of why the instrument sounds the way it does.
Strummed open, with nothing fretted, the strings spell C. That is what makes a tuning like this useful for slide playing and drones – a full chord is one straight barre away at any fret. See C shapes in this tuning →
Slack key on a ukulele does what slack key does on a guitar: it slackens a string until the open instrument sounds a chord. Here the A string comes down to G, leaving an open C major.
The tuning belongs to Hawaiian playing, where the ukulele and the slack key guitar grew up together. With a full chord already ringing, accompaniment becomes a matter of small movements rather than full shapes.
History
Where the Slack Key (GCEG) tuning comes from
G-C-E-G retunes the A string down a whole step to make an open C chord. It borrows the idea of Hawaiian slack-key guitar, where strings are “slackened” to open chords, and is used for Hawaiian-style ukulele pieces.
Other Ukulele tunings
Alternative
Chords for this tuning
How do I tune my Ukulele to Slack Key (GCEG)?
Allow microphone access, pluck a string, and the tuner will detect it automatically. The needle shows whether the string is flat or sharp – adjust until the reading is within ±5 cents (G-C-E-G).
Which notes are used in Slack Key (GCEG) tuning?
Slack Key (GCEG) tuning for Ukulele uses the notes G-C-E-G, listed from the lowest string to the highest.
Can I tune without a microphone?
Yes. Every string card plays a reference tone – tap it and match your string to the sound by ear.