Semitone / halftone / half step

What is a semitone, halftone or half step in music?

A semitone is the smallest interval used to measure a distance between two different pitches notated by notes in Western music theory. On piano, it’s the distance between two adjacent keys. On guitar and ukulele, it’s the next fret up or down the fretboard. Read on to get the full explanation.

Notes can be located closeby or far apart from each other. This distance is measured by musical intervals consisting of semitones (also called halftone or half step) and/or whole tones.

Let’s look at two examples of musical intervals. First, the minor second interval consists of one semitone. Second, the minor third interval consists of three semitones (or one whole tone and one semitone).

What is a semitone on piano?

Let’s imagine a piano keyboard. Remember that some white keys are separated by a black key and some are not.

Simply put, a semitone is the distance between two adjacent keys — black or white. 

For instance, G# and A are adjacent keys. Therefore, these notes are separated from each other at a distance of a semitone. The same goes for E and F.

Semitone on piano

Keep in mind that black keys can have different names depending on the musical situation. For instance, the G# from the example above can be called Ab at certain moments. This phenomenon is called the enharmonic equivalent.

What is a semitone on guitar?

A semitone distance on guitar is the next fret up or down.

Let’s take the example of the B and C notes. Looking at the piano keyboard, we can see that B and C are adjacent keys. Therefore, it’s a semitone. On guitar, the B note is located on the thinnest string seventh fret. So we need to move to the next fret up the neck to find the C note. Right, it’ll be eight fret.

Semitone on guitar

What is a semitone on ukulele?

The same goes for the ukulele fretboard. A semitone distance is the next fret up or down.

Let’s stick with the example of the B and C notes. The B note is located on the thinnest string second fret. In order to find the C note we need to move one fret up the neck, landing on the third fret.

semitone on ukulele

Further reading: 

Whole tone

Music interval Perfect fourth

Music interval Perfect fifth