Introduction
There's two main types of tuning for the ukulele: re-entrant, where the 1st string is tuned an octave higher to give a brighter sound when strumming, and regular, where the stings ascend in pitch from the first string (lowest) to the last string (highest). Note that by regular I don't mean regular for ukuleles, but regular for most stringed instruments (guitar, bass, violin, etc.).
Re-entrant Tuning in C
The most common tuning for soprano and concert ukuleles is re-entrant GCEA. As stated above, re-entrant tuning means is that the the 1st string (in this case G) is tuned an octave higher to give the uke a brighter sound when strumming, so the actual notes are: first string: G4, second string: C4, third string: E4, and fourth: A4. When played together, they make a C6 chord.
Tuning Methods
From a Keyboard
If you have an electronic keyboard (or an acoustic if it's in tune), you can tune the uke with it. First match the C string to middle C (C4), then the E string to the E just above it (E4), then the G string to the G just above that (G4) then the A to the A just above that (A4).
From a Tuned C String
To tune the uke from the C string you first need to make sure the C string in tune. Then tune the E string by holding down the C string on the fourth fret and tuning the E string to match it. Then the G string by holding down the E string on the third fret and tuning the G string to match it. And lastly, the A string by holding the G string down on the second fret and tuning the A string to match it.
Fretboard
The following is the notes of the ukulele's first 12 frets when it is tuned in re-entrant GCEA tuning:
0 1 2 3 4 5 6 7 8 9 10 11 12
+---A---||-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|
+---E---||---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|
+---C---||-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|
+---G---||-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|
Re-entrant Tuning in D
Before amplification technology, ukulele performers used to tune their ukes a whole step higher to get more volume. This resulted in the ADF#B tuning which, when played together, makes the D6 chord. This tuning, along with the re-entrant in C tuning are sometimes called "My dog has fleas" because the order of the notes when the strings are played first to last is the same as the order of the notes of the title phrase of the song "My Dog Has Fleas". The notes are the same as the re-entrant GCEA except each is one whole step (two piano keys including the black ones) higher, so the first string is A4, the second, D4, the third, F#4, the last, B4. This setup is primarily used on soprano and concert ukes.
Tuning Methods
From a Keyboard
First match the D string to the D above middle C (D4), then the F# string to the F# just above that D (F#4), then the A string to the A just above that (A4), and the B to the B just above that (B4).
From a Tuned D String
To tune the uke from the D string you first need to make sure the D string in tune. Then tune the F# string by holding down the D string on the fourth fret and tuning the F# string to match it. Then the A string by holding down the F# string on the third fret and tuning the A string to match it. And lastly, the B string by holding the A string down on the second fret and tuning the B string to match it. It's the same as the C tuning, except you start with D.
Fretboard
The following is the notes of the ukulele's first 12 frets when it is tuned in re-entrant ADF#B tuning:
0 1 2 3 4 5 6 7 8 9 10 11 12
+---B---||---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|
+-F#/Gb-||---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|
+---D---||-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|
+---A---||-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|
Regular Tuning in C
Now that we're done with the two re-entrant tunings, it's time for standard tuning. Used mainly on tenor and concert ukuleles, standard tuning in C is the same as re-entrant C tuning, except the G string is an octave lower, so the notes are G3, C4, E4, and A4. Because the G is an octave lower, this tuning is also called low G tuning.
Tuning Methods
From a Keyboard
First match the G string to the G just below middle C (G3), then the C string to middle C (C4), then the E string to the E just above that (E4) and the A to the A just above that (A4).
From a Tuned G String
First tune the G string to G3, Then tune the C tring by holding down the G string on the fifth fret and tuning the C string to match it. Then the E string by holding down the C string on the fourth fret and tuning the E string to match it. And finally, the A string by holding the E string down on the fifth fret and tuning the A string to match it.
Fretboard
The following is the notes of the ukulele's first 12 frets when it is tuned in low G tuning:
0 1 2 3 4 5 6 7 8 9 10 11 12
+---A---||-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|
+---E---||---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|
+---C---||-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|
+---G---||-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|
Regular Tuning in G
The last tuning is regular tuning in the key of G, the standard for baritone ukes. This tuning is actually the same
as the four high strings of the standard EADGBE tuning of the guitar.
Tuning Methods
From a Keyboard
First match the D string to the D below middle C (D3), then the G string to the G after that D (G3, then the B string to the B just above that (B3) and the E to the E just above that (E3).
From a Tuned D String
First tune the D string to D3, Then tune the G string by holding down the D string on the fifth fret and tuning the G string to match it. Then the B string by holding down the G string on the fourth fret and tuning the B string to match it. And finally, the E string by holding the B string down on the fifth fret and tuning the E string to match it.
Fretboard
The following is the notes of the ukulele's first 12 frets when it is tuned in re-entrant GCEA tuning:
0 1 2 3 4 5 6 7 8 9 10 11 12
+---E---||---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|
+---B---||---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|
+---G---||-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|
+---D---||-D#/Eb-|---E---|---F---|-F#/Gb-|---G---|-G#/Ab-|---A---|-A#/Bb-|---B---|---C---|-C#/Db-|---D---|
