A transposing instrument reads a different note than is sounded. For example, when a Bb trumpeter (transposing) plays the written note C, it is the same note as what a pianist (non-transposing) would read as the Bb below that. If an Eb alto saxophone (transposing) plays a written C, it sounds an Eb below that on the piano, or other “concert” instruments.

Three terms to understand, related to this:

• Written: The note as it appears in the notation, which is usually transposed

• Concert: The non-transposed note, which is what most people would hear
• Transposed: The note shifted to suit the instrument

The reason why instruments do this is that they are constructed for an optimal sound. The range may not sit nicely on the standard staff, and so rather than have many ledger lines, the notation is instead transposed. This makes the individual parts easier to read. The guitar, for example, actually transposes an octave lower than is written.

A conductor’s score may be written with the transpositions as the individual instrumentalists see them, or it might be a concert score, where none of the instruments transpose. Whether a score is written or transposed must be indicated, to avoid confusion. Generally, the transposition is included with the instrument name next to its staff. Conductors often study sight-reading in various clefs to help them make an easy translation/transposition, for communication and analysis purposes. For example, in tenor clef, the note C is on the second staff line from the top.

If we pretend that a Bb trumpet part is written in tenor clef, it becomes similar to a trumpet reading the note D and the listener hearing a concert C, and so on. Games we play....

Transposition should not be confused with the pitch that an instrument is based upon. For example, the tenor trombone is build around the note Bb, as is the Bb trumpet, but the trombone does not transpose. It simply mostly easily plays the note Bb and its associated fundamentals with the slide in its default position. Some past notation practices would name this instrument as a Bb trombone, but this is confusing, as the common convention now is to only list an instrument’s pitch when the note is actually transposing. (More confusing: a significant body of work for the trombone is set in treble clef, in which case it does in fact transpose. But this is not currently a common practice.)

Some instruments also come in non-transposing forms. For example, a C trumpet reads in concert pitch. It is a different instrument, though, than a Bb trumpet.

Here is a list of some common instruments and their transpositions. Remember, when the instrument plays a C, the transposed note is what sounds. (The octave varies, though, so if that’s important to find out what that is.)

• Piccolo (Sounds an octave higher)
• Bb Clarinet
• Bb Bass Clarinet
• Eb English Horn
• Bb Soprano Saxophone
• Eb Alto Saxophone
• Bb Tenor Saxophone
• Eb Baritone Saxophone
• Bb Trumpet
• F Horn
• Guitar (Sounds an octave lower)
• Bass (Sound an octave lower)