Cent

Currency

A cent is one-hundredth subdivision of several units of currency, including the various dollars and the euro.

In the United States and Canada, the symbol ¢ is used for the cent, thus: 50¢ means "fifty cents". In HTML, it is displayed with the code ¢. The symbol is used only with numbers less than 100. The common name for a one cent piece in the United States and Canada is penny.

Music

In music, the cent is a logarithmic measure of relative pitch or intervals. 1200 cents are equal to one octave, and an equally tempered semitone is equal to 100 cents. The formula to determine the value in cents between two notes with frequencies a and b is:

<math>n = 1200 \log_2 \left( \frac{a}{b} \right) </math>

The measure was developed by A. J. Ellis[?] around the 1870s, and was published in his edition of Hermann von Helmholtz's On the Sensations of Tone. It has since become the standard way of measuring intervals.