Tuning: G C E A

The G string is tuned higher than the C next to it, so the four open strings sound G4 C4 E4 A4: 392, 262, 330 and 440 hertz.

My dog has fleas

Hold the ukulele with the neck to your left (if you are right-handed) and look at the strings from the top: the one nearest your chin is string 4, tuned to G. Then come C, E and A, with string 1, the A, nearest the floor. Plucked one after another, from G down to A, they sing the four notes of an old tuning jingle, "My dog has fleas". The notes are G4, C4, E4 and A4. Together they form a C6 chord, which is why this is called C tuning, and why strumming all four open strings already sounds like a pleasant chord.

Notice something odd: the G string is not the lowest. G4 is seven semitones above C4. On a guitar the strings go steadily from low to high, but on a standard ukulele the pitch goes up from C to E to A and then jumps back to a high G on the outside. This is called re-entrant tuning, and it is a big part of the ukulele sound. It puts all four strings close together in pitch, so chords sound bright and tight, and a melody can move across strings in small steps. Some players, especially on tenor ukuleles, use a thicker string tuned an octave lower, G3, called low G, which gives a fuller bass.

The frequencies come from the same formula used for every note in this site’s music courses: f = 440 × 2^((m − 69) ÷ 12), where m is the note number and 69 is the A above middle C. The A string is exactly 440 hertz, the usual tuning reference. Low G at 196 hertz is half of high G’s 392, as an octave always is. An electronic clip-on tuner reads these frequencies from the vibration of the headstock and shows how far each string is from its target.

Tuning the strings to each other

Without a tuner you can still tune the ukulele to itself once one string is right. Tune the A string to a reference. Press the E string at the 5th fret: that note is A4, so adjust the E string until it matches the open A. Press the C string at the 4th fret to get E4 and match it to the open E. Finally press the G string at the 2nd fret to get A4 and match it to the open A. With low G, press the G string at the 5th fret instead, which gives C4, and match it to the open C. Turn a peg slowly and pluck while you turn; the pitch should slide up to the target rather than past it.