Clarinet (A) Transposition

A transposing instrument reads music written at a different pitch than it sounds. The written part is shifted so the player’s fingerings stay consistent across the family, while a piano (a concert-pitch, non-transposing instrument) sounds exactly what is on the page. That mismatch is why a Clarinet (A) playing from a piano’s sheet music will sound in the wrong key unless the part is transposed first.

Written → concert notes

What each written note sounds like at concert (piano) pitch on the Clarinet (A):

Written note	Sounds (concert)
C	A
D	B
E	C♯
F	D
G	E
A	F♯
B	G♯

Key-signature conversion (concert → written)

To turn a piano (concert) key into the Clarinet (A)’s written key, move up a minor third:

Concert (piano) key	Written key
C major	E♭ major
G major	B♭ major
D major	F major
A major	C major
F major	A♭ major
B♭ major	D♭ major
E♭ major	G♭ major
A♭ major	C♭ major

Why the Clarinet (A) is pitched in A

Instruments in a family are built in different keys so a player can move between them without relearning fingerings. On the Clarinet (A), the same fingering that produces a written C sounds concert A; writing the part up a minor third lets the player keep those familiar fingerings. For the pianist, the practical takeaway is the reverse: hand a Clarinet (A) player your concert-pitch music transposed up a minor third, or you’ll be a minor third apart.