Ask a Maestro: Why do instruments transpose?

The rule of thumb when writing for transposing instruments: whatever the key of the instrument, that’s the note that comes out when the player plays a C. Keep that in mind and you won’t have to keep looking things up.

Another way to think about transposing instruments:

  • For non-transposing instruments, the musical score is a description of the final result. It is up to the performer to decide how to achieve the notes on the page (which string to play a note on, which fingering to use, etc.)
  • For transposing instruments, the musical score is a set of instructions: it tells you where to put your fingers when. The musical result is achieved if you follow the instructions accurately.

A couple extra tips:

  • Horn in F sounds a fifth below written, while trumpet in F sounds a fourth above. Because screw you!
  • Horn in C: that’s not a transposing instrument right? Wrong!! It sounds an octave below written. Because screw you double!


Charles L.

Don’t forget the genius of the tuba family. They have different pitched instruments, Bb, C, Eb, F, etc, but their parts are always in C. They don’t “transpose;” they just learn a different set of fingerings for each instrument.


So true Charles! To the point where I don’t even think of the tuba as a transposing instrument. It just goes to show that the logic works both ways!


Also, I feel like, more and more, trumpets work this way – when writing for professional orchestras, most composers now just write the part in C and the players choose whether they want to play it on B-flat, C or D. But of course, the big difference is that trumpet isn’t taught this way – everyone learns on a B-flat trumpet and they learn it as a transposing instrument. Maybe this will change…

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