Serious work on the composition is estimated to have begun around the autumn of 1817, with its completion in 1818. It was simultaneously published in 1819 by publishers across Europe, including Artaria in Vienna (which could be considered a global simultaneous publication), and the work is dedicated to Archduke Rudolf.

The nickname "Hammerklavier" has become established, originating from the title page of the first edition score, which states "Große Sonate für das Hammerklavier" (Grand Sonata for the Hammerklavier). However, this phrase was also used for other sonatas.

According to Arata Kojima, Beethoven composed the first to third movements of this work on a Viennese Streicher instrument with triple strings and a 6-octave range (F0-F7), and the fourth movement on a London-made piano sent by a friend from London.

The Viennese and London instruments differed in action; the Streicher instrument allowed the hammer position to be shifted from three strings to one string via a una corda pedal. However, it was the unique timbre of the London-made instrument that captivated Beethoven. It is certain that this instrument had a decisive influence on his later compositions.

Movement 1: B-flat Major, 2/2 time, Sonata Form

Exposition

The main theme, consisting of a resolute chordal motive spanning over four octaves and a contrasting cantabile-like motive, expands its range to five octaves. Following a thematic statement where forte and piano alternate every measure, and a transition developing the opening motive, the subordinate theme is presented in G major, a minor third below. From this theme, successive musical ideas are spun out, and another subordinate theme appears in G major with triplets and long trills. This theme leads into the codetta.

Development and Recapitulation

Repeating the codetta motive and modulating to E-flat major, a four-voice fugato based on the main theme's motive is developed. This is then broken down into the rhythmic material (eighth note + quarter note) that constitutes the motive.

The development of this material connects to the figuration in the exposition's transition, and the subordinate theme's material is developed in B minor, but quickly leads to the main theme's rhythmic motive. The tonality shifts to B major, and the repetition of this motive leads to the recapitulation of the main theme.

In the recapitulation, elements developed in the fugato are contrapuntally combined with the main theme. The cantabile-like melody also undergoes intricate contrapuntal manipulation.

Both subordinate themes are recapitulated in the tonic B-flat major.

Coda

The codetta motive from the exposition is extended; first the second subordinate theme appears, then the first, after which fragments of the main theme are repeated with a wide dynamic range. The dynamic alternation between forte and piano gradually becomes more urgent, reaching a point of alternation every beat, then fades into a vanishing pianissimo.

This sonata-form movement concludes with a thorough, fragmentary treatment of the main theme's motive.

Movement 2: B-flat Major, 3/4 time, Scherzo

The main section features a theme consisting of the repetition of a short motive with a dotted-rhythm anacrusis. In the classical four-movement structure, there are no other instances in sonatas where a scherzo is placed as the second movement (though Sonata No. 18 has a 2/4 time scherzo as the second movement, its third movement is a minuet, so it cannot be understood in the same context); examples can be found in works like the Symphony No. 9, Op. 125.

The trio is in the parallel minor, B-flat minor. It returns to the main section after a transition featuring Presto 2/4 time and Prestissimo scale passages ascending through the entire available range. There are no repeat signs or da capo indications.

Movement 3: F-sharp Minor, 6/8 time

An Adagio movement that maximally utilizes the structural characteristics of an instrument with a shifting keyboard (una corda). F-sharp minor is the enharmonic equivalent of G-flat minor, a third below the tonic, and here too, tonal construction based on a third relationship is observed.

The harmonic opening theme in F-sharp minor makes it difficult to identify specific motives that constitute the theme, constructing a long musical idea while avoiding simple repetition. This is followed by a second theme played over fragmentary chords and syncopated inner voices. Then, modulating to D major, a third theme appears, where characteristic rhythmic motives of the tonic and dominant are repeated above and below a figure that ornaments two continuously sustained notes.

It returns to F-sharp minor, but the opening theme retains only its harmonic progression in the bass voice, with the upper voices intricately ornamented. This clarifies that the opening theme's "characteristic was its lack of motivic distinctiveness." The second theme is recapitulated in D major, and the third theme in F-sharp major.

The third theme further appears in G major, a portion of the opening theme returns, and it concludes in F-sharp major.

Some discuss this movement as a sonata form, but no motivic development techniques for the themes can be found, and the fantasia-like character of this movement seems to resist "hearing its form." If one were to formally interpret it, it might be considered a large two-part form with, for example, three themes.

Movement 4: B-flat Major, 4/4 time / 3/4 time

The introduction, beginning with the repetition of F, a semitone below the previous movement, seems to be exploring tonality throughout. It passes through G-flat major, B major, G-sharp minor, etc., reaching A major. Amidst the repeated A notes, the bass progresses to F, functioning as the dominant of the main section's B-flat major.

The main section is marked "Fuga tre voci, con alcune licenze" (Three-voice fugue, with some liberties). The fugue subject is highly distinctive, featuring a leap of a tenth, trills, and chromatic alterations added to a sequential progression of sixteenth notes. The countersubject has a rhythmic characteristic with an accent on the second beat, and the subsequent free section is in a complementary rhythmic relationship with the countersubject.

In the next section, it modulates to A-flat major, and the fugue develops with the latter half of the fugue subject, the latter half of the countersubject, and a new countersubject progressing sequentially in thirds/sixths. It then shifts to G-flat major, E-flat minor, D-flat major, A-flat major, etc., and a fugato develops, utilizing even musical ideas spun from the subject and trills as motives.

A new section in B minor begins, and the fugue develops with the retrograde form of the subject. After a half cadence on the dominant of D minor, it becomes a cantabile-style fugue with a new subject in D major. It transitions to B-flat major, and the original fugue subject enters. This is accompanied by variations of previously appeared subjects and countersubjects, and further recalls motives with an organ point trill in the bass. Finally, the piece concludes with a portion of the fugue subject and octave trills.