Online Ukulele Tuner

Tune a ukulele in 5 steps

1. Hold the ukulele as if you were playing: the string closest to your chin is the 4th string, G.
2. Place your phone about 20 cm (8 inches) from the sound hole and pluck the G string with your thumb.
3. Tighten the string if the indicator is on the left; if it is on the right, loosen it a little below the note, then bring it back up.
4. Continue with C, E and then A. The tuner automatically switches to the nearest string.
5. Strum a C chord (one finger on the 3rd fret of the A string): if it sounds right, your ukulele is ready.

Notes and frequencies

GCEA: the notes of the ukulele

Soprano, concert and tenor ukuleles are tuned G, C, E, A, hence the name “GCEA”. In scientific pitch notation, the four strings sound G4 (392 Hz), C4 (261.63 Hz), E4 (329.63 Hz) and A4 (440 Hz). The A string is exactly the A of the standard reference pitch.

These notes form a C major chord with an added sixth, which is why the four open strings already sound pleasant together. The C, E and A strings match the notes of a guitar with a capo on the 5th fret, on its four highest strings, with one difference: the G string.

Reentrant tuning explained

On a guitar, the strings go from low to high. On a standard ukulele, they don't: the 4th string, G4 at 392 Hz, is higher than the 3rd string, C4 at 261.63 Hz. This is called reentrant tuning, because the sequence of notes “re-enters” higher up instead of descending steadily.

That high G gives the ukulele its bright tone and close-voiced chords. It is also a trap when tuning: if you assume the G string should be the lowest, you tune it down an octave, or worse, you try to raise the C above the G and the string breaks. The tuner knows the reentrant order and targets the right octave for each string.

Low G, D tuning and baritone ukulele

• Low G: the 4th string is replaced by a thicker string tuned an octave lower, to G3 at 196 Hz. The ukulele gains bass and the tuning becomes linear. You need a string made for it, often wound: a high-G string slackened by an octave would sound floppy.
• D tuning (A, D, F♯, B): each string goes up a whole step from GCEA. This older tuning sounds even brighter but increases tension; keep it for small sopranos with suitable strings, and tune up slowly.
• Baritone ukulele: larger, it is tuned D, G, B, E (D3, G3, B3, E4), like the four highest strings of a guitar. Guitar chord shapes apply directly.

Strings that stretch a lot

Ukulele strings, whether nylon or fluorocarbon, stretch noticeably during the first few days. A freshly restrung ukulele can go out of tune within minutes: retune often, gently stretch each string and be patient, it settles quickly.

Ukulele tuners are often friction pegs or geared tuners arranged 2+2. The tuner shows a diagram of the headstock and watches, while you turn, whether the note goes up or down, so you don't spend ages turning the wrong way.

For kids and classrooms

Guided mode walks through the four strings one after another with a simple visual cue. The LED or large-number display can be read from across the room, and the reference tone lets students sing the note before tuning to it. The app is free, with no ads and no account, which makes it easy to use in class.