Key Transposition Calculator — Transpose Music Keys

Transposition means moving all the notes of a piece of music up or down by the same interval (number of semitones). This changes the key while preserving all the melodic and harmonic relationships.

Common reasons include matching a singer's vocal range, making a piece easier to play on a particular instrument, accommodating transposing instruments (like Bb trumpet or Eb saxophone), or key-matching tracks for DJ mixing.

Half step = 1 semitone, whole step = 2, minor third = 3, major third = 4, perfect fourth = 5, tritone = 6, perfect fifth = 7, octave = 12. Transposing by 12 semitones returns to the same note name, one octave higher.

Note names are spelled to match the resulting key signature. The flat keys (F, Bb, Eb, Ab, Db) and their chords are written with flats, so transposing C up a perfect fourth gives F major whose IV chord is Bb (not A#). The remaining keys (C, G, D, A, E, B, F#) are written with sharps.

Every major key shares its exact notes with a minor key whose tonic lies a minor third below — for example C major and A minor share the same key signature. The calculator can show the relative minor of the transposed key when the option is enabled.