HesapHanem

Musical Interval Calculator

Identify the interval between two notes.

How it is calculated

Each note is chosen from the twelve chromatic names C, C#, D, D#, E, F, F#, G, G#, A, A# and B (there are no flat names; use the sharp for the same key) and given an octave number. The tool turns every note into a position on the keyboard, position = (octave + 1) × 12 + note index with C = 0 up to B = 11, and the distance is semitones = |position₂ − position₁|. The order of the two notes does not matter: the result is always the absolute distance, with no up or down. For 0 to 12 semitones it gives the interval name, from Unison and Minor 2nd to Perfect 5th, Major 7th and Octave. Above 12 semitones it shows only the count, not a compound name such as a major tenth.

Worked example

Take C in octave 4 and A in octave 4. C is index 0 and A is index 9, and both are in the same octave, so the positions are 60 and 69. The distance is 69 − 60 = 9 semitones, which is shown as 9. Nine semitones is called a Major 6th, so that is the name the tool gives. Reversing the notes, A4 to C4, gives the same 9 and the same name, because the tool measures distance only. C4 up to E5 would give 16 and the label 16 semitones.

Try this example →

Common mistakes

  • Expecting flat names such as Eb or Bb in the list. Only sharps are offered, so choose D# for Eb; both are the same pitch for the semitone count.
  • Expecting the result to show direction. Whether the second note is above or below the first, the answer is the same, so C4 to A4 and A4 to C4 both give 9.
  • Leaving the octave numbers the same when the notes are meant to be an octave apart. C4 to C4 is a Unison (0); you must change one octave number to get 12.
  • Expecting a name for intervals larger than an octave. Above 12 semitones the tool gives only the count, such as 16 semitones, not a major tenth.
  • Confusing an augmented 4th and a diminished 5th. Both are 6 semitones and the tool shows them as the same Tritone, since it counts pitch distance and not note spelling.

About this calculator

This calculator finds the number of semitones between two musical notes and names the resulting interval (e.g. major third, perfect fifth, minor seventh) using standard Western music theory, counting the distance on the chromatic scale and classifying it by quality (major, minor, perfect, augmented, diminished) and size.

Musicians, composers, music students, and ear-training apps use it to identify intervals when transcribing music by ear, to check chord and scale construction, and to understand harmony and voice leading.

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Comments (1)

  • Editorial team

    The tool stops naming at an octave, but you can finish the job by hand: subtract 12 from the semitone count and name the remainder. C4 up to E5 shows 16 semitones, which is an octave plus 4 semitones, so a major 10th. The tool also gives no direction. Which compound interval names would you like to see added?

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