A chord diagram is the pictorial representation of a chord or a scale. The strings of an ukulele are shown as lines in a rectangular line network.

Mostly the representation is vertical; then the top horizontal line represents the neck of the fretboard, and the vertical lines mark the strings (from left to right: 4^th, 3^rd, 2^nd, 1^st string; thus, in C6 tuning: G-C-E-A). Then the horizontal lines point to the frets; the top line is either the zero fret (i.e. the open string) or, if there is a (mostly Roman) number next to the diagram, the corresponding fret. This is the same perspective as holding the ukulele upside down and looking at the fretboard.

When viewed horizontally, the vertical lines represent the frets and the horizontal lines represent the strings. This corresponds to the view of the fingerboard, if you hold the ukulele to play in front of your belly.

Black dots mark the points on the fingerboard where the fingers have to be placed to play. The root note of the chord is often additionally bordered. White points above the first fret indicate an empty string, an X at this point indicates a string to be damped.

Below the string lines, the numbers of the fingers of the fret hand to be used can also be noted with Latin numerals.