Twelve recessions occurred since the end of WWII. The length of the shortest recession was 2 months. The length of the longest recession was 18 months. The average length of a recession was approximately 10 months. The NBER is the National Bureau of Economic Research they're a private, nonpartisan organization that facilitates cutting-edge investigation and analysis of major economic issues.

U.S. Business Cycle Expansions and Contractions Source: National Bureau of Economic Research Duration Peak month Trough month of Recession Months) November 1948 October 1949 11 July 1953 May 1954 10 August 1957 April 1958 April 1960 February 1961 10 December 1969 November 1970 11 November 1973 March 1975 16 January 1980 July 1980 6 July 1981 November 1982 16 July 1990 March 1991 8 March 2001 November 2001 8 December 2007 June 2009 18 February 2020 April 2020 2 This table shows the length of recessions in the U.S. since the end of WWII. The dates of recessions are determined by the Business Cycle Dating Committee of the NBER