On the equally tempered scale the frequency ratio for each semitone is 1.0595:1. The ratio for the tone interval is the sixth root of 2 and that for the semitone the twelfth root of 2.

If the pitch of a note is increased by an octave the frequency is doubled.

Note | C | D | E | F | G | A | B | C' |

Frequency (Hz) | 262 | 295 | 328 | 349 | 393 | 440 | 491 | 524 |

Ratio (f/f_{C} |
1 | 9/8 | 5/4 | 4/3 | 3/2 | 5/3 | 15/8 | 2 |