Only 172 of Beethoven's works have opus numbers, divided among 138 opus numbers. Many works that were unpublished or else published without opus numbers have been assigned either "WoO" (Werke ohne Opuszahl—works without opus number), Hess or Biamonti numbers.

How many pieces of music did Beethoven write in total?

Recognised as one of the greatest and most influential composers of the Western classical tradition, he defied the onset of deafness from the age of 28 to produce an output that encompasses 722 works, including 9 symphonies, 35 piano sonatas and 16 string quartets.

How many piano sonatas did Beethoven write in his life?

Ludwig van Beethoven wrote his 35 piano sonatas between 1782 and 1822. Although originally not intended to be a meaningful whole, as a set they comprise one of the most important collections of works in the history of music.