HesapHanem

Music Transpose Calculator

Shift a note by any number of semitones.

How it is calculated

Each note is converted to a MIDI-style number: n = (octave + 1) × 12 + p, where p is the pitch class from 0 (C) to 11 (B), counting sharps only (C, C#, D, D#, E, F, F#, G, G#, A, A#, B). The shift in semitones is added: n' = n + s. The new octave is ⌊n' / 12⌋ − 1 and the new note is the name at position n' mod 12.

Octave numbering follows the convention in which middle C is C4. Decimal semitones are cut to a whole number, negative values move down, and a result below 0 gives no answer. Results always use sharps, so a flat such as Bb appears as A#.

Worked example

Start with A in octave 4, shift up 5 semitones. A has pitch class 9, so n = (4 + 1) × 12 + 9 = 69. Add 5: n' = 74. Octave = ⌊74 / 12⌋ − 1 = 6 − 1 = 5. Position 74 mod 12 = 2, which is D. The tool shows D5.

Try this example →

Common mistakes

  • Counting the starting note as step one: moving up a musical "fifth" is 7 semitones, not 5, and a "fourth" is 5.
  • Entering a transposition in whole tones instead of semitones; one whole tone equals 2 semitones.
  • Expecting flat names: the result is spelled with sharps, so D# and Eb are the same pitch here.
  • Using a different octave convention than the tool, where middle C is C4; some software calls it C3 or C5.

About this calculator

This calculator transposes a musical note up or down by a given number of semitones, returning the resulting note name and octave. Transposition shifts every note in a piece by the same interval, moving the whole piece to a different key while preserving the relationships between notes — for example, shifting up 2 semitones moves C to D and turns a song in C major into D major.

Musicians, arrangers, and vocal coaches use transposition to fit a song to a different instrument's range (like moving a piece written for B♭ trumpet to concert pitch) or a singer's vocal range, and composers use it when modulating between keys. Positive semitone counts move a note up and negative counts move it down.

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Comments (1)

  • Editorial team

    Notes are entered with sharps only, so a flat key such as B flat has to be typed as A#. The semitone shift is a whole number, which suits a guitar capo: capo on fret 3 is simply +3. Moving a song down for a singer means a negative shift. A result below C-1 on the MIDI scale returns nothing. Playing something unusual, such as a transposing horn? Describe the interval you need and we may add presets.

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