As with the Piano Concerto No. 2, this C major concerto reflects Beethoven's assimilation of the styles of Mozart and Haydn, while its abrupt harmonic shifts demonstrate Beethoven's musical personality. It adheres to the concerto variant of sonata form.
I. Allegro con brio
Tempo: = 144
The first movement is in sonata form, but with an added orchestral exposition, a cadenza, and a coda. It has a main theme repeated many times, and there are several subordinate themes. The orchestral exposition changes keys many times, but the second exposition is mainly in G major. The development starts in E-flat major, then modulates to C minor, which ends with an octave glissando, which is merely played as a scale with right hand on the upper notes, and left hand on the lower notes. The recapitulation is in C major.
There are three options for the cadenza to this movement, all of which vary in length and difficulty and all ending with trills. The coda is played by the orchestra alone. Average performances vary in length from sixteen to eighteen minutes.
The second movement is in the key of A-flat major, in this context a key relatively remote from the concerto's opening key of C major. If the movement adhered to traditional form, its key would be F major, the subdominant key.
Like many slow movements, this movement is in ternary (ABA) form. Its opening A section presents several themes that are then developed in the middle B section.
Typical performances last more than ten minutes.
III. Rondo. Allegro scherzando
The third movement is a seven-part rondo (ABACABA), a traditional third-movement form in classical concerti. The piano states the main theme, which is then repeated by the orchestra. The two B sections (subordinate themes) are in G major and C major respectively. The middle section is in A minor.
Two short cadenzas are indicated by Beethoven in this movement, one just before the final return to the main theme, and a short eingang immediately before the end of the movement, which finishes with a striking dynamic contrast; the piano plays a melody quietly, but the orchestra then ends the movement forcefully.
The movement typically lasts around eight to nine minutes.
The Canadian pianist Glenn Gould wrote his own cadenza to Beethoven's Piano Concerto No.1. It was published by Barger and Barclay.