Our grand piano pictured above is kind of tiny but it illustrates the piano keyboard nicely.  If you play all of the keys on the piano, including the black ones, beginning on a C note, you will play 12 notes before you play another C.

Some of the notes have two different names. The 2nd note (the first black piano key after the C note) may be called C# (pronounced C sharp) or it may be called Db (pronounced D flat). If you are ascending the scale you would probably refer to the notes as sharps (C, C#, D, D#, etc.). If you are descending on the scale it is usually easier to refer to the notes as flats (E, Eb, D, Db, C, B, Bb, and so on).

As you can see by looking at the piano keyboard above, there is a sharp (or flat) between all of the notes except B and C and between E and F. This is more fully explained in the tutorial on the Major Scale.

All of the other scales such as major, minor, pentatonic, or whatever, are subsets of the chromatic scale. This is logical since the chromatic scale uses every possible note.

The following charts list the notes on the guitar, banjo, and ukulele. Each fret is a note on the chromatic scale. Each increment in the chromatic scale is called a half step. Therefore, one fret is a half step. Two frets is a whole step. Notice that if you begin by playing any open string and continue up the neck a half step at a time, when you reach the 12th fret you have completed the entire chromatic scale and have arrived at the note you began with (although an octave higher).