Wolfgang Amadeus Mozart was a prolific composer and wrote in many genres. Perhaps his best-admired work is in opera, the piano concerto and sonata, the symphony, and in the string quartet and string quintet. Mozart also wrote much work for solo piano, other forms of chamber music, masses and other religious music, and numerous dances, divertimentos, and other forms of light entertainment.
Mozart's symphonic production covers a 24-year interval, from 1764 to 1788. According to most recent investigations, Mozart wrote not just the 41 symphonies reported in traditional editions, but up to 68 complete works of this type. However, by convention, the original numbering has been retained, and so his last symphony is still known as "No. 41". Some of the symphonies (K. 297, 385, 550) were revised by the author after their first versions.
These are the numbered symphonies from Mozart's early childhood.
There are also several "unnumbered" symphonies from this time period. Many of them were given numbers past 41 (but not in chronological order) in an older collection of Mozart's works (Mozart-Werke, 1877–1910, referred to as "GA"), but newer collections refer to them only by their entries in the Köchel catalogue. Many of these cannot be definitively established as having been written by Mozart (see here).
These symphonies are sometimes subcategorized as "Early" (1771–1773) and "Late" (1773–1777), and sometimes subcategorized as "Germanic" (with minuet) or "Italian" (without minuet). None of these were printed during Mozart's lifetime.
Although not counted as "symphonies" the three Divertimenti K. 136–138, in 3-movement Italian overture style, are sometimes indicated as "Salzburg Symphonies" too.
There are also several "unnumbered" symphonies from this time period that make use of music from Mozart's operas from the same time period. They are also given numbers past 41.