How long did the battle of Austerlitz last?

The combined battles were each about a day long, but separated by 18 days.

The battle of Saratoga was actually two separate battles, on September 19 and on October 7, 1777. In the Battle of Freeman's Farm (Sept. 19), British General Thomas Burgoyne pushed back the forces under Horatio Gates. However, a similar attempt failed 18 days later at the Battle of Bemis Heights, and Burgoyne's army was surrounded by the American forces at Saratoga. On October 17, he surrendered.