Instrument Transposition Calculator

A transposing instrument is one that produces a different pitch than written. When a trumpet player reads a written C, they produce a Bb concert pitch. This is why musicians must transpose when sharing parts or writing for mixed ensembles.

Common transposing instruments and their intervals:

How to transpose:

• Concert → Bb instrument: raise the written note by a major 2nd (2 semitones)
• Concert → Eb instrument: raise by a major 6th (9 semitones)
• Concert → F instrument: raise by a perfect 5th (7 semitones)
• Bb instrument → Concert: lower by a major 2nd

Key signatures also change: When transposing, key signatures shift by the same interval. A concert piece in C major is written in D major for a Bb trumpet. A concert piece in F major is written in G major for a Bb clarinet.

Tip for arrangers: Always think in concert pitch when composing, then transpose each instrument’s part separately. DAWs and notation software (Sibelius, Finale, MuseScore) can transpose automatically, but understanding the theory is what lets you catch it when the software has guessed the wrong enharmonic spelling.

On spelling. Gb major and F# major are the same six black-and-white keys, but one is written with six flats and the other with six sharps, and an engraver picks whichever costs fewer accidentals. The calculator names the target key the same way, so what it prints is what you would actually see at the top of the part.