MusicReasonProgression, Transposition, and Arranging
How do I move this progression to another key?
Type a chord progression, pick a source and destination key, and get every root and bass note respelled for the new key, with the structure of each chord preserved exactly.
Answer
Your progression text stays in your browser. It is never stored, logged, or sent anywhere, and it never appears in analytics or a share URL.
Want to learn more? Transposition for Voice, Instruments, and Arranging
Understand
Transposition here preserves harmonic distance, not your original open-string playability or a vocal range's suitability: a progression that was easy to play or sing in one key is not guaranteed to remain easy after moving it, even though the harmonic relationships are identical. If the new key is awkward on your instrument or voice, that's a separate decision this tool does not make for you.
Worked example
The progression C, F, G, C transposed from C major up to D major (two semitones) becomes D, G, A, D. Every root moved by the same two semitones and was respelled using D major's own sharp-preferring context, rather than a fixed semitone-name lookup that ignores the destination key.
Method and limitations
Each token is parsed into a root letter and accidental, a quality suffix, and an optional slash bass. The tool computes the chromatic distance between the source and destination tonic, shifts every parsed root and bass by that distance, and respells the result using the destination key's accidental preference. Quality suffix text is preserved verbatim once it is recognized as a supported chord-quality expression; unparsed or unrecognized tokens are marked and never transposed by guessing from surrounding text. This tool does not know whether your progression is actually in the source key you selected: source key is a transposition reference, not a key-detection claim.