It is scored for flute, 2 oboes, 2 clarinets, 2 bassoons, 2 horns, 2 trumpets, timpani and strings. Of the Mozart piano concertos, this one has the most extensive scoring. (It is the only one scored for both oboes and clarinets.) It is also the only late Mozart piano concerto in which the soloist plays after the cadenza in the first movement, here adorning an orchestral argument based on the extremely chromaticopening theme of the work with arpeggios, all the way through to the quiet close. It is one of only two minor-key piano concertos (the other being No. 20 in D Minor), and one of only three concertos where the first movement is in 3/4 time (the others being No. 11 and No. 14).
The concerto has long been considered one of Mozart's greatest works. Arthur Hutchings has described it as the most "concerted" of all the concertos (i.e. the most integrated). Girdlestone has also effectively claimed it as the greatest. Ludwig van Beethoven took particular inspiration for his own music from this concerto. Richard Strauss played his own cadenza for the concerto in 1885.
Jonathan Stock has analysed in detail Mozart's use of woodwind timbre in the instrumentation of the concerto's slow movement. Chris Goertzen has mapped the structure of the slow movement.
The concerto was first published in orchestral parts in c.1800 by Johann André of Offenbach am Main. The manuscript of the concerto resides at the Royal College of Music.