G string — G4 in standard tuning
The top string is usually a high G, which gives ukulele its bright, close-position sound. Low-G players replace it with G3, one octave lower.
C string — C4
The C string is the lowest-pitched string in standard high-G tuning. It is also the thickest of the four standard strings.
E string — E4
The E string sits between C and A in pitch and is used in many familiar beginner melodies.
A string — A4
The bottom string is A at 440 Hz—the same pitch commonly used as an orchestral tuning reference.
Ukulele string notes in order
Hold the instrument in a normal playing position and look from the string nearest your face toward the string nearest the floor. The standard High-G sequence is G4, C4, E4 and A4. Players sometimes call these the fourth, third, second and first strings. Numbering begins with the string nearest the floor, so the visual top string is called the fourth string.
This order does not change for a left-handed player, although the instrument may be restrung or held in the opposite orientation. Use the sounding note and string number rather than relying only on “top” or “bottom,” because those words can mean different things in diagrams and conversations.
Frequencies for GCEA tuning
With A4 set to 440 Hz, the High-G targets are G4 at approximately 392.00 Hz, C4 at 261.63 Hz, E4 at 329.63 Hz and A4 at 440.00 Hz. Notice that G4 is higher than C4. That non-linear order is called re-entrant tuning and creates the compact, bright character associated with a traditional ukulele.
Frequency is useful when checking an octave, but beginners can rely on the note label and center indicator. A tuner may briefly identify an overtone after a hard pluck, so play gently, mute the other strings and wait for the sustained part of the note before adjusting.
High-G, Low-G and baritone notes
Low-G tuning keeps the letters GCEA but changes the fourth string from G4 to G3, approximately 196.00 Hz. The lower G produces a linear pitch sequence and extends the instrument’s range. Use a string made for Low-G rather than loosening an ordinary High-G string by an octave.
A baritone ukulele normally uses D3, G3, B3 and E4. Those notes match the four highest strings of a guitar and require a baritone string set. Always choose the tuner mode that matches the instrument and installed strings before changing tension.
How the string notes form chords
Open-string notes are the foundation for every chord shape. Fretting a string shortens its vibrating length and raises the pitch by one semitone for each fret. For example, the open C string becomes C-sharp at the first fret and D at the second. Understanding the four open notes makes chord diagrams, scales and troubleshooting easier to read.
If one note in a familiar chord sounds wrong, play each string separately. A fretted note can sound sharp when excessive finger pressure bends the string, even if the open string is correctly tuned. Check the open note first, then use light pressure close behind the fret.