Ukulele Slack Key Tuner — Tune to Slack Key in Your Browser
Mic-based chromatic tuner pre-set to Slack Key. No download, no sign-up, works in your browser.
Tuning summary
- Notes (low to high)
- G4 · C4 · E4 · G4
- Instrument
- Ukulele
- About this tuning
- Hawaiian slack-key uke variant — drops the A to G for an open C major sonority across all four strings.
Start tuning
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About Slack Key on ukulele
Ukulele slack-key tuning is a Hawaiian-derived variant that drops the A string down to G, giving G4, C4, E4, G4 — the open strings now spell a C major triad with three different pitches instead of four (the open G appears twice, once high and once a fifth below the high G). The slug 'slack-key' references the Hawaiian guitar tradition of ki ho'alu, where strings are 'slacked' from standard pitch into open chord tunings.
The musical effect is to put a complete C major chord under the unfretted strings. Strumming open produces a clean major triad rather than the C6 of standard re-entrant tuning. This makes melodies that resolve to C feel grounded and effortless, and it suits the gentle, often single-line melodic phrasing that Hawaiian slack-key style favours. The simpler open chord also makes barre-style chord movement easier — a barre at any fret produces a major chord rooted at that fret.
Slack-key style on ukulele draws from the Hawaiian acoustic tradition. The actual ki ho'alu lineage lives more on the guitar than the ukulele, but adapting the open-major-chord aesthetic to a ukulele is common in Hawaiian and contemporary island-influenced playing. The tuning is rare in non-Hawaiian repertoire, which is part of its charm — it produces a sound immediately recognisable as deliberately island-flavoured.
If you are coming from standard re-entrant tuning, the only change is the first string (A) dropped a whole step to G. Every chord shape that did not use the A string is unchanged. Chords that did use the A string need rethinking — a C major no longer needs the third fret of the A string because the open string is already part of the chord. Try strumming open and adding a barre at the second fret (D), fifth fret (F), or seventh fret (G) for a quick survey of the major-chord vocabulary.
Frequently asked questions
- Is ukulele slack-key the same as guitar slack-key?
- No — Hawaiian slack-key is primarily a guitar tradition. The ukulele variant borrows the open-tuning idea but applies it to four strings instead of six.
- Will I need different strings for slack-key?
- No — your standard set works. The first string drops a whole step from A to G, which is gentle on the string.
- Does slack-key tuning put extra stress on the neck?
- No — it slightly reduces tension because the first string drops in pitch. The other three strings are unchanged.
- Can I play standard ukulele songs in slack-key?
- Songs that do not use the first string transfer unchanged. Songs that rely on fretted notes on the A string need re-fingering, since the open A is now an open G.
- How do I quickly switch back to standard?
- Raise the first string from G back to A — a single whole step. The other three strings stay where they are.