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.

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.

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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.