Editing Interval (music) (section)

=== Cents ===
{{Main|Cent (music)}}

The standard system for comparing interval sizes is with [[Cent (music)|cents]]. The cent is a [[logarithmic scale|logarithmic]] unit of measurement. If frequency is expressed in a [[logarithmic scale]], and along that scale the distance between a given frequency and its double (also called [[octave]]) is divided into 1200 equal parts, each of these parts is one cent. In twelve-tone [[equal temperament]] (12-TET), a tuning system in which all [[semitone]]s have the same size, the size of one semitone is exactly 100 cents. Hence, in 12-TET the cent can be also defined as one hundredth of a [[semitone]].

Mathematically, the size in cents of the interval from frequency ''f''<sub>1</sub> to frequency ''f''<sub>2</sub> is

<math display="block">n = 1200 \cdot \log_2 \left( \frac{f_2}{f_1} \right)</math>