An interval is the difference between two musical notes: the distance between two frequencies, often expressed in semitones (or cents). The below tool calculates the exact number of semitones between any two given frequencies, or, given a frequency and an interval, will calculate the note required to achieve that interval.

Some facts:

  • A semitone is equal to 100 cents.
  • The twelve-tone equal temperament scale divides an octave into 12 semitones (of 100 cents each).
  • A theoretical model of an equidistant heptatonic scale, where all the intervals of the seven-note scale were perfectly equal, would result in an interval of 1.714 semitones each (171.4 cents).

Calculation of Semitone Intervals

Enter any two known values: either the two notes, or one of the notes and the known interval. Press "calculate" to solve for the remaining value. Two (and no more than two) fields are required.




Studying the “Equidistant” scale of Fula flutes

This tool is useful to me in studying and analyzing the tuning used by flutemakers in West Africa, who do not tune to a Western scale, but rather tune to the scale that “sounds right” to them according to how they know a particular melody should sound. By comparing the intervals between each of the notes of the scale, we can get a better sense of the exact nature of this often “equidistant” scale preferred by that instrument maker.

By understanding the exact scale used, I can then easily replicate the tonal “color” characteristics of a particlar scale when constructing a flute and/or transposing into another key. This is useful also when two or more matching flutes are needed, but when the scale does not fit within the framework of our Western tuning.